diff --git a/poetry.lock b/poetry.lock
index 5275a0fa..35a6689b 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -207,17 +207,17 @@ python-versions = "*"
 
 [[package]]
 name = "flake8"
-version = "3.9.0"
+version = "4.0.1"
 description = "the modular source code checker: pep8 pyflakes and co"
 category = "dev"
 optional = false
-python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
+python-versions = ">=3.6"
 
 [package.dependencies]
-importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
+importlib-metadata = {version = "<4.3", markers = "python_version < \"3.8\""}
 mccabe = ">=0.6.0,<0.7.0"
-pycodestyle = ">=2.7.0,<2.8.0"
-pyflakes = ">=2.3.0,<2.4.0"
+pycodestyle = ">=2.8.0,<2.9.0"
+pyflakes = ">=2.4.0,<2.5.0"
 
 [[package]]
 name = "flake8-bandit"
@@ -521,11 +521,11 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [[package]]
 name = "pycodestyle"
-version = "2.7.0"
+version = "2.8.0"
 description = "Python style guide checker"
 category = "dev"
 optional = false
-python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*"
 
 [[package]]
 name = "pydocstyle"
@@ -540,7 +540,7 @@ snowballstemmer = "*"
 
 [[package]]
 name = "pyflakes"
-version = "2.3.0"
+version = "2.4.0"
 description = "passive checker of Python programs"
 category = "dev"
 optional = false
@@ -965,7 +965,7 @@ testing = ["pytest (>=3.5,!=3.7.3)", "pytest-checkdocs (>=1.2.3)", "pytest-flake
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7.0"
-content-hash = "5cad4ed21ff84c53df1dd297b255b5f2f29a9fb446e1bbdb37fc51a11f5e6729"
+content-hash = "0e4b4901bea1dfb348d2fc97aa94089478234a123c5f294a9314db48cf2d6592"
 
 [metadata.files]
 alabaster = [
@@ -1098,8 +1098,8 @@ filelock = [
     {file = "filelock-3.0.12.tar.gz", hash = "sha256:18d82244ee114f543149c66a6e0c14e9c4f8a1044b5cdaadd0f82159d6a6ff59"},
 ]
 flake8 = [
-    {file = "flake8-3.9.0-py2.py3-none-any.whl", hash = "sha256:12d05ab02614b6aee8df7c36b97d1a3b2372761222b19b58621355e82acddcff"},
-    {file = "flake8-3.9.0.tar.gz", hash = "sha256:78873e372b12b093da7b5e5ed302e8ad9e988b38b063b61ad937f26ca58fc5f0"},
+    {file = "flake8-4.0.1-py2.py3-none-any.whl", hash = "sha256:479b1304f72536a55948cb40a32dce8bb0ffe3501e26eaf292c7e60eb5e0428d"},
+    {file = "flake8-4.0.1.tar.gz", hash = "sha256:806e034dda44114815e23c16ef92f95c91e4c71100ff52813adf7132a6ad870d"},
 ]
 flake8-bandit = [
     {file = "flake8_bandit-2.1.2.tar.gz", hash = "sha256:687fc8da2e4a239b206af2e54a90093572a60d0954f3054e23690739b0b0de3b"},
@@ -1277,16 +1277,16 @@ py = [
     {file = "py-1.10.0.tar.gz", hash = "sha256:21b81bda15b66ef5e1a777a21c4dcd9c20ad3efd0b3f817e7a809035269e1bd3"},
 ]
 pycodestyle = [
-    {file = "pycodestyle-2.7.0-py2.py3-none-any.whl", hash = "sha256:514f76d918fcc0b55c6680472f0a37970994e07bbb80725808c17089be302068"},
-    {file = "pycodestyle-2.7.0.tar.gz", hash = "sha256:c389c1d06bf7904078ca03399a4816f974a1d590090fecea0c63ec26ebaf1cef"},
+    {file = "pycodestyle-2.8.0-py2.py3-none-any.whl", hash = "sha256:720f8b39dde8b293825e7ff02c475f3077124006db4f440dcbc9a20b76548a20"},
+    {file = "pycodestyle-2.8.0.tar.gz", hash = "sha256:eddd5847ef438ea1c7870ca7eb78a9d47ce0cdb4851a5523949f2601d0cbbe7f"},
 ]
 pydocstyle = [
     {file = "pydocstyle-5.1.1-py3-none-any.whl", hash = "sha256:aca749e190a01726a4fb472dd4ef23b5c9da7b9205c0a7857c06533de13fd678"},
     {file = "pydocstyle-5.1.1.tar.gz", hash = "sha256:19b86fa8617ed916776a11cd8bc0197e5b9856d5433b777f51a3defe13075325"},
 ]
 pyflakes = [
-    {file = "pyflakes-2.3.0-py2.py3-none-any.whl", hash = "sha256:910208209dcea632721cb58363d0f72913d9e8cf64dc6f8ae2e02a3609aba40d"},
-    {file = "pyflakes-2.3.0.tar.gz", hash = "sha256:e59fd8e750e588358f1b8885e5a4751203a0516e0ee6d34811089ac294c8806f"},
+    {file = "pyflakes-2.4.0-py2.py3-none-any.whl", hash = "sha256:3bb3a3f256f4b7968c9c788781e4ff07dce46bdf12339dcda61053375426ee2e"},
+    {file = "pyflakes-2.4.0.tar.gz", hash = "sha256:05a85c2872edf37a4ed30b0cce2f6093e1d0581f8c19d7393122da7e25b2b24c"},
 ]
 pygments = [
     {file = "Pygments-2.8.1-py3-none-any.whl", hash = "sha256:534ef71d539ae97d4c3a4cf7d6f110f214b0e687e92f9cb9d2a3b0d3101289c8"},
diff --git a/pyproject.toml b/pyproject.toml
index 1b0e290b..e9181fe8 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -44,7 +44,7 @@ xdoctest = {extras = ["colors"], version = "^0.15.0"}
 sphinx = "^3.5.3"
 sphinx-autobuild = "^2021.3.14"
 pre-commit = "^2.11.1"
-flake8 = "^3.9.0"
+flake8 = "^4.0.1"
 black = "^20.8b1"
 flake8-bandit = "^2.1.2"
 flake8-bugbear = "^21.4.3"