diff --git a/poetry.lock b/poetry.lock
index a10f468523d8efefa64c12117a898fb21a636263..e313d91a90c0ea6355a7d97a9c06eadc8abc4e69 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -189,17 +189,17 @@ python-versions = "*"
 
 [[package]]
 name = "flake8"
-version = "3.8.4"
+version = "3.9.0"
 description = "the modular source code checker: pep8 pyflakes and co"
 category = "dev"
 optional = false
-python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,>=2.7"
+python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,>=2.7"
 
 [package.dependencies]
 importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
 mccabe = ">=0.6.0,<0.7.0"
-pycodestyle = ">=2.6.0a1,<2.7.0"
-pyflakes = ">=2.2.0,<2.3.0"
+pycodestyle = ">=2.7.0,<2.8.0"
+pyflakes = ">=2.3.0,<2.4.0"
 
 [[package]]
 name = "flake8-bandit"
@@ -524,7 +524,7 @@ python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
 [[package]]
 name = "pycodestyle"
-version = "2.6.0"
+version = "2.7.0"
 description = "Python style guide checker"
 category = "dev"
 optional = false
@@ -543,7 +543,7 @@ snowballstemmer = "*"
 
 [[package]]
 name = "pyflakes"
-version = "2.2.0"
+version = "2.3.0"
 description = "passive checker of Python programs"
 category = "dev"
 optional = false
@@ -1029,7 +1029,7 @@ testing = ["pytest (>=3.5,!=3.7.3)", "pytest-checkdocs (>=1.2.3)", "pytest-flake
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.6"
-content-hash = "69127f8bb7f65ff3630a8608c1e021499b09d49a948f598ff25d384c987312f1"
+content-hash = "27b3696482dac8b72b845b09b52dbf3386b4581610e18c1f2ed1efcf4cb0eda1"
 
 [metadata.files]
 alabaster = [
@@ -1152,8 +1152,8 @@ filelock = [
     {file = "filelock-3.0.12.tar.gz", hash = "sha256:18d82244ee114f543149c66a6e0c14e9c4f8a1044b5cdaadd0f82159d6a6ff59"},
 ]
 flake8 = [
-    {file = "flake8-3.8.4-py2.py3-none-any.whl", hash = "sha256:749dbbd6bfd0cf1318af27bf97a14e28e5ff548ef8e5b1566ccfb25a11e7c839"},
-    {file = "flake8-3.8.4.tar.gz", hash = "sha256:aadae8761ec651813c24be05c6f7b4680857ef6afaae4651a4eccaef97ce6c3b"},
+    {file = "flake8-3.9.0-py2.py3-none-any.whl", hash = "sha256:12d05ab02614b6aee8df7c36b97d1a3b2372761222b19b58621355e82acddcff"},
+    {file = "flake8-3.9.0.tar.gz", hash = "sha256:78873e372b12b093da7b5e5ed302e8ad9e988b38b063b61ad937f26ca58fc5f0"},
 ]
 flake8-bandit = [
     {file = "flake8_bandit-2.1.2.tar.gz", hash = "sha256:687fc8da2e4a239b206af2e54a90093572a60d0954f3054e23690739b0b0de3b"},
@@ -1368,16 +1368,16 @@ py = [
     {file = "py-1.10.0.tar.gz", hash = "sha256:21b81bda15b66ef5e1a777a21c4dcd9c20ad3efd0b3f817e7a809035269e1bd3"},
 ]
 pycodestyle = [
-    {file = "pycodestyle-2.6.0-py2.py3-none-any.whl", hash = "sha256:2295e7b2f6b5bd100585ebcb1f616591b652db8a741695b3d8f5d28bdc934367"},
-    {file = "pycodestyle-2.6.0.tar.gz", hash = "sha256:c58a7d2815e0e8d7972bf1803331fb0152f867bd89adf8a01dfd55085434192e"},
+    {file = "pycodestyle-2.7.0-py2.py3-none-any.whl", hash = "sha256:514f76d918fcc0b55c6680472f0a37970994e07bbb80725808c17089be302068"},
+    {file = "pycodestyle-2.7.0.tar.gz", hash = "sha256:c389c1d06bf7904078ca03399a4816f974a1d590090fecea0c63ec26ebaf1cef"},
 ]
 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-2.2.0-py2.py3-none-any.whl", hash = "sha256:0d94e0e05a19e57a99444b6ddcf9a6eb2e5c68d3ca1e98e90707af8152c90a92"},
-    {file = "pyflakes-2.2.0.tar.gz", hash = "sha256:35b2d75ee967ea93b55750aa9edbbf72813e06a66ba54438df2cfac9e3c27fc8"},
+    {file = "pyflakes-2.3.0-py2.py3-none-any.whl", hash = "sha256:910208209dcea632721cb58363d0f72913d9e8cf64dc6f8ae2e02a3609aba40d"},
+    {file = "pyflakes-2.3.0.tar.gz", hash = "sha256:e59fd8e750e588358f1b8885e5a4751203a0516e0ee6d34811089ac294c8806f"},
 ]
 pygments = [
     {file = "Pygments-2.7.4-py3-none-any.whl", hash = "sha256:bc9591213a8f0e0ca1a5e68a479b4887fdc3e75d0774e5c71c31920c427de435"},
@@ -1425,18 +1425,26 @@ pyyaml = [
     {file = "PyYAML-5.4.1-cp27-cp27mu-manylinux1_x86_64.whl", hash = "sha256:bb4191dfc9306777bc594117aee052446b3fa88737cd13b7188d0e7aa8162185"},
     {file = "PyYAML-5.4.1-cp36-cp36m-macosx_10_9_x86_64.whl", hash = "sha256:6c78645d400265a062508ae399b60b8c167bf003db364ecb26dcab2bda048253"},
     {file = "PyYAML-5.4.1-cp36-cp36m-manylinux1_x86_64.whl", hash = "sha256:4e0583d24c881e14342eaf4ec5fbc97f934b999a6828693a99157fde912540cc"},
+    {file = "PyYAML-5.4.1-cp36-cp36m-manylinux2014_aarch64.whl", hash = "sha256:72a01f726a9c7851ca9bfad6fd09ca4e090a023c00945ea05ba1638c09dc3347"},
+    {file = "PyYAML-5.4.1-cp36-cp36m-manylinux2014_s390x.whl", hash = "sha256:895f61ef02e8fed38159bb70f7e100e00f471eae2bc838cd0f4ebb21e28f8541"},
     {file = "PyYAML-5.4.1-cp36-cp36m-win32.whl", hash = "sha256:3bd0e463264cf257d1ffd2e40223b197271046d09dadf73a0fe82b9c1fc385a5"},
     {file = "PyYAML-5.4.1-cp36-cp36m-win_amd64.whl", hash = "sha256:e4fac90784481d221a8e4b1162afa7c47ed953be40d31ab4629ae917510051df"},
     {file = "PyYAML-5.4.1-cp37-cp37m-macosx_10_9_x86_64.whl", hash = "sha256:5accb17103e43963b80e6f837831f38d314a0495500067cb25afab2e8d7a4018"},
     {file = "PyYAML-5.4.1-cp37-cp37m-manylinux1_x86_64.whl", hash = "sha256:e1d4970ea66be07ae37a3c2e48b5ec63f7ba6804bdddfdbd3cfd954d25a82e63"},
+    {file = "PyYAML-5.4.1-cp37-cp37m-manylinux2014_aarch64.whl", hash = "sha256:cb333c16912324fd5f769fff6bc5de372e9e7a202247b48870bc251ed40239aa"},
+    {file = "PyYAML-5.4.1-cp37-cp37m-manylinux2014_s390x.whl", hash = "sha256:fe69978f3f768926cfa37b867e3843918e012cf83f680806599ddce33c2c68b0"},
     {file = "PyYAML-5.4.1-cp37-cp37m-win32.whl", hash = "sha256:dd5de0646207f053eb0d6c74ae45ba98c3395a571a2891858e87df7c9b9bd51b"},
     {file = "PyYAML-5.4.1-cp37-cp37m-win_amd64.whl", hash = "sha256:08682f6b72c722394747bddaf0aa62277e02557c0fd1c42cb853016a38f8dedf"},
     {file = "PyYAML-5.4.1-cp38-cp38-macosx_10_9_x86_64.whl", hash = "sha256:d2d9808ea7b4af864f35ea216be506ecec180628aced0704e34aca0b040ffe46"},
     {file = "PyYAML-5.4.1-cp38-cp38-manylinux1_x86_64.whl", hash = "sha256:8c1be557ee92a20f184922c7b6424e8ab6691788e6d86137c5d93c1a6ec1b8fb"},
+    {file = "PyYAML-5.4.1-cp38-cp38-manylinux2014_aarch64.whl", hash = "sha256:fd7f6999a8070df521b6384004ef42833b9bd62cfee11a09bda1079b4b704247"},
+    {file = "PyYAML-5.4.1-cp38-cp38-manylinux2014_s390x.whl", hash = "sha256:bfb51918d4ff3d77c1c856a9699f8492c612cde32fd3bcd344af9be34999bfdc"},
     {file = "PyYAML-5.4.1-cp38-cp38-win32.whl", hash = "sha256:fa5ae20527d8e831e8230cbffd9f8fe952815b2b7dae6ffec25318803a7528fc"},
     {file = "PyYAML-5.4.1-cp38-cp38-win_amd64.whl", hash = "sha256:0f5f5786c0e09baddcd8b4b45f20a7b5d61a7e7e99846e3c799b05c7c53fa696"},
     {file = "PyYAML-5.4.1-cp39-cp39-macosx_10_9_x86_64.whl", hash = "sha256:294db365efa064d00b8d1ef65d8ea2c3426ac366c0c4368d930bf1c5fb497f77"},
     {file = "PyYAML-5.4.1-cp39-cp39-manylinux1_x86_64.whl", hash = "sha256:74c1485f7707cf707a7aef42ef6322b8f97921bd89be2ab6317fd782c2d53183"},
+    {file = "PyYAML-5.4.1-cp39-cp39-manylinux2014_aarch64.whl", hash = "sha256:d483ad4e639292c90170eb6f7783ad19490e7a8defb3e46f97dfe4bacae89122"},
+    {file = "PyYAML-5.4.1-cp39-cp39-manylinux2014_s390x.whl", hash = "sha256:fdc842473cd33f45ff6bce46aea678a54e3d21f1b61a7750ce3c498eedfe25d6"},
     {file = "PyYAML-5.4.1-cp39-cp39-win32.whl", hash = "sha256:49d4cdd9065b9b6e206d0595fee27a96b5dd22618e7520c33204a4a3239d5b10"},
     {file = "PyYAML-5.4.1-cp39-cp39-win_amd64.whl", hash = "sha256:c20cfa2d49991c8b4147af39859b167664f2ad4561704ee74c1de03318e898db"},
     {file = "PyYAML-5.4.1.tar.gz", hash = "sha256:607774cbba28732bfa802b54baa7484215f530991055bb562efbed5b2f20a45e"},
diff --git a/pyproject.toml b/pyproject.toml
index 111be7d341bb8d8fdb68de911a6c5e29af39f028..1410a1fc6f46b75d682bca686f31806d477949e0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,7 +16,7 @@ sphinx = "^3.5"
 sphinx-autodoc-typehints = "^1.7"
 pytest = "^6.0"
 safety = "^1.8.5"
-flake8 = "^3.7.9"
+flake8 = "^3.9.0"
 flake8-fixme = "^1.1.1"
 flake8-mypy = "^17.8.0"
 flake8-bandit = "^2.1.2"