diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 50ae8057..550ff458 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -11,17 +11,15 @@ repos:
       - id: debug-statements
       - id: destroyed-symlinks
       - id: trailing-whitespace
-  # will be uncommented when all the
-  # scripts have been revised once
-  # - repo: https://github.com/psf/black
-  #   rev: 23.1.0
-  #   hooks:
-  #     - id: black
-  # - repo: https://github.com/PyCQA/isort
-  #   rev: 5.12.0
-  #   hooks:
-  #     - id: isort
-  # - repo: https://github.com/PyCQA/flake8
-  #   rev: 6.0.0
-  #   hooks:
-  #     - id: flake8
+  - repo: https://github.com/psf/black
+    rev: 23.1.0
+    hooks:
+      - id: black
+  - repo: https://github.com/PyCQA/isort
+    rev: 5.12.0
+    hooks:
+      - id: isort
+  - repo: https://github.com/PyCQA/flake8
+    rev: 5.0.4
+    hooks:
+      - id: flake8
diff --git a/docs/gen_docs.py b/docs/gen_docs.py
index 3e1d790a..fdfbe088 100644
--- a/docs/gen_docs.py
+++ b/docs/gen_docs.py
@@ -1,15 +1,17 @@
 """Generate docs."""
 
 # standard
-from shutil import copy, move, rmtree
-from yaml import safe_load, safe_dump
+from shutil import rmtree, move, copy
 from ast import parse, ImportFrom
-from typing import Dict, List
+from typing import List, Dict
 from os.path import getsize
 from subprocess import run
 from pathlib import Path
 from sys import argv
 
+# external
+from yaml import safe_load, safe_dump
+
 
 def _write_ref_content(source: Path, module_name: str, func_name: str):
     """Write content."""
@@ -61,7 +63,7 @@ def generate_documentation(source: Path):
     # build docs as subprocess
     print(run(("mkdocs", "build"), capture_output=True).stderr.decode())
     # restore mkdocs config
-    move(source / "mkdocs.bak.yml", source / "mkdocs.yml")
+    move(str(source / "mkdocs.bak.yml"), source / "mkdocs.yml")
 
 
 if __name__ == "__main__":
diff --git a/poetry.lock b/poetry.lock
index 32d21038..cff62878 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -865,6 +865,21 @@ nodeenv = ">=0.11.1"
 pyyaml = ">=5.1"
 virtualenv = ">=20.10.0"
 
+[[package]]
+name = "pyaml"
+version = "21.10.1"
+description = "PyYAML-based module to produce pretty and readable YAML-serialized data"
+category = "dev"
+optional = false
+python-versions = "*"
+files = [
+    {file = "pyaml-21.10.1-py2.py3-none-any.whl", hash = "sha256:19985ed303c3a985de4cf8fd329b6d0a5a5b5c9035ea240eccc709ebacbaf4a0"},
+    {file = "pyaml-21.10.1.tar.gz", hash = "sha256:c6519fee13bf06e3bb3f20cacdea8eba9140385a7c2546df5dbae4887f768383"},
+]
+
+[package.dependencies]
+PyYAML = "*"
+
 [[package]]
 name = "pycodestyle"
 version = "2.9.1"
@@ -1439,4 +1454,4 @@ testing = ["big-O", "flake8 (<5)", "jaraco.functools", "jaraco.itertools", "more
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.8"
-content-hash = "0d3d02b694099f712d6ebec660a6854bca91b1ebebad0f81be5805b1974c9923"
+content-hash = "50370d78d455974d8323b523c02050900a5570ce08657757a1666a03c92fdca1"
diff --git a/pyproject.toml b/pyproject.toml
index 22794f5e..ceef7924 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -35,6 +35,7 @@ tox = "^4.4.7"
 mkdocs = "^1.4.2"
 mkdocs-material = "^9.1.3"
 mkdocstrings = { extras = ["python"], version = "^0.20.0" }
+pyaml = "^21.10.1"
 
 [tool.poetry.group.sast.dependencies]
 bandit = "^1.7.5"
@@ -60,38 +61,31 @@ build-backend = "poetry.core.masonry.api"
 [tool.black]
 line-length = 100
 target-version = ["py38", "py39", "py310", "py311"]
+extend-exclude = "i18n"
 
 [tool.bandit]
-exclude_dirs = [
-    ".github",
-    ".pytest_cache",
-    ".tox",
-    ".vscode",
-    "docs",
-    "site",
-    "tests",
-]
+exclude_dirs = [".github", ".pytest_cache", ".tox", ".vscode", "site", "tests"]
 
 [tool.isort]
-extend_skip_glob = ["**/i18n/*"]
 ensure_newline_before_comments = true
+extend_skip_glob = ["**/i18n/*"]
 force_grid_wrap = 0
 force_sort_within_sections = true
 ignore_comments = true
 include_trailing_comma = true
 known_local_folder = ["validators"]
-line_length = 100
 length_sort = true
+line_length = 100
 multi_line_output = 3
 profile = "black"
-reverse_sort = true
 reverse_relative = true
+reverse_sort = true
 skip_gitignore = true
 use_parentheses = true
 
 [tool.pyright]
 include = ["validators", "tests"]
-exclude = ["**/__pycache__", ".pytest_cache/", ".tox/", "site/"]
+exclude = ["**/__pycache__", ".pytest_cache/", ".tox/", "site/", "**/i18n/*"]
 pythonVersion = "3.8"
 pythonPlatform = "All"
 typeCheckingMode = "strict"
@@ -102,25 +96,32 @@ legacy_tox_ini = """
     requires =
         tox >= 4.0
     env_list = py{38,39,310,311}
-        # format, lint, type,
+        fmt_black, fmt_isort, lint, type
 
     [testenv]
     description = run unit tests
     deps = pytest
     commands = pytest
 
-    # [testenv:format]
-    # description = run formatter
-    # deps = black
-    # commands = black
-
-    # [testenv:lint]
-    # description = run linters
-    # deps = flake8
-    # commands = flake8
-
-    # [testenv:type]
-    # description = run type checker
-    # deps = pyright
-    # commands = pyright
+    [testenv:fmt_black]
+    description = run formatter
+    deps = black
+    commands = black .
+
+    [testenv:fmt_isort]
+    description = run formatter
+    deps = isort
+    commands = isort .
+
+    [testenv:lint]
+    description = run linters
+    deps = flake8
+    commands = flake8
+
+    [testenv:type]
+    description = run type checker
+    deps =
+        pyright
+        pytest
+    commands = pyright
 """
diff --git a/setup.cfg b/setup.cfg
index 038b70ab..9c1f4026 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,5 +1,6 @@
 # until https://github.com/PyCQA/flake8/issues/234 is resolved
 
 [flake8]
-max-line-length = 100
 docstring-convention = google
+exclude = __pycache__,.github,.pytest_cache,.tox,.vscode,site,i18n
+max-line-length = 100
diff --git a/tests/test__extremes.py b/tests/test__extremes.py
index 6b98ffc4..c575c650 100644
--- a/tests/test__extremes.py
+++ b/tests/test__extremes.py
@@ -7,8 +7,8 @@
 # external
 import pytest
 
-# project
-from validators._extremes import AbsMax, AbsMin
+# local
+from validators._extremes import AbsMin, AbsMax
 
 abs_max = AbsMax()
 abs_min = AbsMin()
diff --git a/tests/test_card.py b/tests/test_card.py
index 95261305..132f847c 100644
--- a/tests/test_card.py
+++ b/tests/test_card.py
@@ -6,7 +6,6 @@
 
 # local
 from validators import (
-    ValidationFailure,
     card_number,
     mastercard,
     unionpay,
@@ -15,6 +14,7 @@
     visa,
     amex,
     jcb,
+    ValidationFailure,
 )
 
 visa_cards = ["4242424242424242", "4000002760003184"]
diff --git a/tests/test_hashes.py b/tests/test_hashes.py
index b1c28178..77cf7515 100644
--- a/tests/test_hashes.py
+++ b/tests/test_hashes.py
@@ -5,8 +5,7 @@
 import pytest
 
 # local
-from validators import md5, sha1, sha224, sha256, sha512, ValidationFailure
-
+from validators import sha512, sha256, sha224, sha1, md5, ValidationFailure
 
 # ==> md5 <== #
 
diff --git a/tests/test_ip_address.py b/tests/test_ip_address.py
index 98a977fa..42bf6956 100644
--- a/tests/test_ip_address.py
+++ b/tests/test_ip_address.py
@@ -5,7 +5,7 @@
 import pytest
 
 # local
-from validators import ipv4, ipv6, ValidationFailure
+from validators import ipv6, ipv4, ValidationFailure
 
 
 @pytest.mark.parametrize(
diff --git a/tests/test_length.py b/tests/test_length.py
index 3c389a36..a9278cd3 100644
--- a/tests/test_length.py
+++ b/tests/test_length.py
@@ -4,7 +4,7 @@
 # external
 import pytest
 
-# project
+# local
 from validators import length, ValidationFailure
 
 
diff --git a/tests/test_url.py b/tests/test_url.py
index 15d9d471..a5d377fa 100644
--- a/tests/test_url.py
+++ b/tests/test_url.py
@@ -5,7 +5,7 @@
 import pytest
 
 # local
-from validators import ValidationFailure, url
+from validators import url, ValidationFailure
 
 
 @pytest.mark.parametrize(
diff --git a/tests/test_validation_failure.py b/tests/test_validation_failure.py
index 75835eb7..1c035c5f 100644
--- a/tests/test_validation_failure.py
+++ b/tests/test_validation_failure.py
@@ -1,10 +1,9 @@
 """Test validation Failure."""
 # -*- coding: utf-8 -*-
 
-# project
+# local
 from validators import between
 
-
 failed_obj_repr = "ValidationFailure(func=between"
 
 
diff --git a/validators/__init__.py b/validators/__init__.py
index 1ba5d816..2e65c350 100644
--- a/validators/__init__.py
+++ b/validators/__init__.py
@@ -1,22 +1,22 @@
 """Validate Anything!"""
 # -*- coding: utf-8 -*-
 
-from .between import between
+from .card import card_number, mastercard, unionpay, discover, diners, visa, amex, jcb
+from .hashes import sha512, sha256, sha224, sha1, md5
+from .utils import validator, ValidationFailure
+from .i18n import fi_business_id, fi_ssn
+from .mac_address import mac_address
 from .btc_address import btc_address
-from .card import amex, card_number, diners, discover, jcb, mastercard, unionpay, visa
-from .domain import domain
-from .email import email
-from .hashes import md5, sha1, sha224, sha256, sha512
+from .ip_address import ipv6, ipv4
 from .hostname import hostname
-from .i18n import fi_business_id, fi_ssn
-from .iban import iban
-from .ip_address import ipv4, ipv6
+from .between import between
 from .length import length
-from .mac_address import mac_address
+from .domain import domain
+from .email import email
+from .uuid import uuid
 from .slug import slug
+from .iban import iban
 from .url import url
-from .utils import ValidationFailure, validator
-from .uuid import uuid
 
 __all__ = (
     "amex",
diff --git a/validators/between.py b/validators/between.py
index 2e713e47..12fe54bb 100644
--- a/validators/between.py
+++ b/validators/between.py
@@ -6,7 +6,7 @@
 from datetime import datetime
 
 # local
-from ._extremes import AbsMax, AbsMin
+from ._extremes import AbsMin, AbsMax
 from .utils import validator
 
 PossibleValueTypes = TypeVar("PossibleValueTypes", int, float, str, datetime)
diff --git a/validators/btc_address.py b/validators/btc_address.py
index 065ae1e0..e8267ddc 100644
--- a/validators/btc_address.py
+++ b/validators/btc_address.py
@@ -50,11 +50,12 @@ def btc_address(value: str, /):
 
     > *New in version 0.18.0*.
     """
-    if value and type(value) is str:
-        return (
-            # segwit pattern
-            re.compile(r"^(bc|tc)[0-3][02-9ac-hj-np-z]{14,74}$").match(value)
-            if value[:2] in ("bc", "tb")
-            else _validate_old_btc_address(value)
-        )
-    return False
+    if not value:
+        return False
+
+    return (
+        # segwit pattern
+        re.compile(r"^(bc|tc)[0-3][02-9ac-hj-np-z]{14,74}$").match(value)
+        if value[:2] in ("bc", "tb")
+        else _validate_old_btc_address(value)
+    )
diff --git a/validators/card.py b/validators/card.py
index 7c48e7ff..62ced1ed 100644
--- a/validators/card.py
+++ b/validators/card.py
@@ -34,6 +34,8 @@ def card_number(value: str, /):
 
     > *New in version 0.15.0*.
     """
+    if not value:
+        return False
     try:
         digits = list(map(int, value))
         odd_sum = sum(digits[-1::-2])
diff --git a/validators/domain.py b/validators/domain.py
index d159a61b..3866ab4f 100644
--- a/validators/domain.py
+++ b/validators/domain.py
@@ -44,6 +44,8 @@ def domain(value: str, /, *, rfc_1034: bool = False, rfc_2782: bool = False):
 
     > *New in version 0.9.0*.
     """
+    if not value:
+        return False
     try:
         return not re.search(r"\s", value) and re.match(
             # First character of the domain
diff --git a/validators/hashes.py b/validators/hashes.py
index 1767dfbc..13fe9e1d 100644
--- a/validators/hashes.py
+++ b/validators/hashes.py
@@ -30,7 +30,7 @@ def md5(value: str, /):
 
     > *New in version 0.12.1*
     """
-    return re.match(r"^[0-9a-f]{32}$", value, re.IGNORECASE)
+    return re.match(r"^[0-9a-f]{32}$", value, re.IGNORECASE) if value else False
 
 
 @validator
@@ -55,7 +55,7 @@ def sha1(value: str, /):
 
     > *New in version 0.12.1*
     """
-    return re.match(r"^[0-9a-f]{40}$", value, re.IGNORECASE)
+    return re.match(r"^[0-9a-f]{40}$", value, re.IGNORECASE) if value else False
 
 
 @validator
@@ -80,7 +80,7 @@ def sha224(value: str, /):
 
     > *New in version 0.12.1*
     """
-    return re.match(r"^[0-9a-f]{56}$", value, re.IGNORECASE)
+    return re.match(r"^[0-9a-f]{56}$", value, re.IGNORECASE) if value else False
 
 
 @validator
@@ -108,7 +108,7 @@ def sha256(value: str, /):
 
     > *New in version 0.12.1*
     """
-    return re.match(r"^[0-9a-f]{64}$", value, re.IGNORECASE)
+    return re.match(r"^[0-9a-f]{64}$", value, re.IGNORECASE) if value else False
 
 
 @validator
@@ -137,4 +137,4 @@ def sha512(value: str, /):
 
     > *New in version 0.12.1*
     """
-    return re.match(r"^[0-9a-f]{128}$", value, re.IGNORECASE)
+    return re.match(r"^[0-9a-f]{128}$", value, re.IGNORECASE) if value else False
diff --git a/validators/hostname.py b/validators/hostname.py
index 50c17a58..071e88a9 100644
--- a/validators/hostname.py
+++ b/validators/hostname.py
@@ -6,7 +6,7 @@
 import re
 
 # local
-from .ip_address import ipv4, ipv6
+from .ip_address import ipv6, ipv4
 from .utils import validator
 from .domain import domain
 
@@ -40,6 +40,8 @@ def _port_validator(value: str):
         if _port_regex().match(f":{port_seg}"):
             return host_seg
 
+    return None
+
 
 @validator
 def hostname(
@@ -103,6 +105,9 @@ def hostname(
 
     > *New in version 0.21.0*.
     """
+    if not value:
+        return False
+
     if may_have_port and (host_seg := _port_validator(value)):
         return (
             (_simple_hostname_regex().match(host_seg) if maybe_simple else False)
diff --git a/validators/iban.py b/validators/iban.py
index 0241912c..a7614fae 100644
--- a/validators/iban.py
+++ b/validators/iban.py
@@ -42,4 +42,8 @@ def iban(value: str, /):
 
     > *New in version 0.8.0*
     """
-    return re.match(r"^[A-Z]{2}[0-9]{2}[A-Z0-9]{11,30}$", value) and _mod_check(value)
+    return (
+        (re.match(r"^[A-Z]{2}[0-9]{2}[A-Z0-9]{11,30}$", value) and _mod_check(value))
+        if value
+        else False
+    )
diff --git a/validators/ip_address.py b/validators/ip_address.py
index 0f2e5a6a..b9e0e382 100644
--- a/validators/ip_address.py
+++ b/validators/ip_address.py
@@ -3,12 +3,12 @@
 
 # standard
 from ipaddress import (
-    AddressValueError,
     NetmaskValueError,
-    IPv4Address,
-    IPv4Network,
-    IPv6Address,
+    AddressValueError,
     IPv6Network,
+    IPv6Address,
+    IPv4Network,
+    IPv4Address,
 )
 
 # local
@@ -56,6 +56,8 @@ def ipv4(value: str, /, *, cidr: bool = True, strict: bool = False):
 
     > *New in version 0.2.0*
     """
+    if not value:
+        return False
     try:
         if cidr and value.count("/") == 1:
             return IPv4Network(value, strict=strict)
@@ -104,6 +106,8 @@ def ipv6(value: str, /, *, cidr: bool = True, strict: bool = False):
 
     > *New in version 0.2.0*
     """
+    if not value:
+        return False
     try:
         if cidr and value.count("/") == 1:
             return IPv6Network(value, strict=strict)
diff --git a/validators/length.py b/validators/length.py
index 4b959017..2b8d756c 100644
--- a/validators/length.py
+++ b/validators/length.py
@@ -2,8 +2,8 @@
 # -*- coding: utf-8 -*-
 
 # local
-from .between import between
 from .utils import validator
+from .between import between
 
 
 @validator
@@ -36,4 +36,4 @@ def length(value: str, /, *, min_val: int = 0, max_val: int = 0):
 
     > *New in version 0.2.0*.
     """
-    return between(len(value), min_val=min_val, max_val=max_val)
+    return between(len(value), min_val=min_val, max_val=max_val) if value else False
diff --git a/validators/mac_address.py b/validators/mac_address.py
index 65e76ccf..06f6285c 100644
--- a/validators/mac_address.py
+++ b/validators/mac_address.py
@@ -34,4 +34,4 @@ def mac_address(value: str, /):
 
     > *New in version 0.2.0*.
     """
-    return re.match(r"^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$", value)
+    return re.match(r"^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$", value) if value else False
diff --git a/validators/slug.py b/validators/slug.py
index fe3d3169..a3fcc681 100644
--- a/validators/slug.py
+++ b/validators/slug.py
@@ -33,4 +33,4 @@ def slug(value: str, /):
 
     > *New in version 0.6.0*.
     """
-    return re.match(r"^[a-z0-9]+(?:-[a-z0-9]+)*$", value)
+    return re.match(r"^[a-z0-9]+(?:-[a-z0-9]+)*$", value) if value else False
diff --git a/validators/url.py b/validators/url.py
index 37616372..116ddf4a 100644
--- a/validators/url.py
+++ b/validators/url.py
@@ -57,7 +57,7 @@ def _validate_auth_segment(value: str):
         return _username_regex().match(value)
     username, password = value.rsplit(":", 1)
     return _username_regex().match(username) and all(
-        char_to_avoid not in password for char_to_avoid in {"/", "?", "#", "@"}
+        char_to_avoid not in password for char_to_avoid in ("/", "?", "#", "@")
     )
 
 
@@ -107,7 +107,7 @@ def _validate_optionals(path: str, query: str, fragment: str):
     if query:
         optional_segments &= bool(_query_regex().match(query.encode("idna").decode("utf-8")))
     if fragment:
-        optional_segments &= all(char_to_avoid not in fragment for char_to_avoid in {"/", "?"})
+        optional_segments &= all(char_to_avoid not in fragment for char_to_avoid in ("/", "?"))
     return optional_segments
 
 
@@ -155,7 +155,7 @@ def url(
             When URL string cannot contain an IPv4 address.
         may_have_port:
             URL string may contain port number.
-        maybe_simple:
+        simple_host:
             URL string maybe only hyphens and alpha-numerals.
         rfc_1034:
             Allow trailing dot in domain/host name.
diff --git a/validators/utils.py b/validators/utils.py
index e8060ec9..ede6f658 100644
--- a/validators/utils.py
+++ b/validators/utils.py
@@ -2,10 +2,10 @@
 # -*- coding: utf-8 -*-
 
 # standard
-from typing import Any, Callable, Dict
+from typing import Callable, Dict, Any
 from inspect import getfullargspec
-from functools import wraps
 from itertools import chain
+from functools import wraps
 
 
 class ValidationFailure(Exception):
diff --git a/validators/uuid.py b/validators/uuid.py
index 69b943f7..fa012502 100644
--- a/validators/uuid.py
+++ b/validators/uuid.py
@@ -36,6 +36,8 @@ def uuid(value: Union[str, UUID], /):
 
     > *New in version 0.2.0*.
     """
+    if not value:
+        return False
     if isinstance(value, UUID):
         return True
     try: