diff --git a/poetry.lock b/poetry.lock
index 9a6ea94..8ad06e2 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -184,7 +184,7 @@ optional = false
 python-versions = ">=3.6"
 
 [package.extras]
-testing = ["sphinx", "flake8", "pytest", "pytest-cov", "pytest-virtualenv", "pytest-xdist"]
+testing = ["pytest-xdist", "pytest-virtualenv", "pytest-cov", "pytest", "flake8", "sphinx"]
 
 [[package]]
 name = "coverage"
@@ -214,10 +214,10 @@ optional = false
 python-versions = "*"
 
 [package.extras]
-all = ["Sphinx (>=1.4.4)", "sphinx-rtd-theme (>=0.1.9)", "check-manifest (>=0.25)", "coverage (>=4.0)", "isort (>=4.2.2)", "mock (>=1.3.0)", "pydocstyle (>=1.0.0)", "pytest-cov (>=1.8.0)", "pytest-pep8 (>=1.0.6)", "pytest (>=2.8.0)", "tox (>=3.7.0)", "numpy (>=1.11.0)"]
-docs = ["Sphinx (>=1.4.4)", "sphinx-rtd-theme (>=0.1.9)"]
+tests = ["tox (>=3.7.0)", "pytest (>=2.8.0)", "pytest-pep8 (>=1.0.6)", "pytest-cov (>=1.8.0)", "pydocstyle (>=1.0.0)", "mock (>=1.3.0)", "isort (>=4.2.2)", "coverage (>=4.0)", "check-manifest (>=0.25)"]
 numpy = ["numpy (>=1.11.0)"]
-tests = ["check-manifest (>=0.25)", "coverage (>=4.0)", "isort (>=4.2.2)", "mock (>=1.3.0)", "pydocstyle (>=1.0.0)", "pytest-cov (>=1.8.0)", "pytest-pep8 (>=1.0.6)", "pytest (>=2.8.0)", "tox (>=3.7.0)"]
+docs = ["sphinx-rtd-theme (>=0.1.9)", "Sphinx (>=1.4.4)"]
+all = ["numpy (>=1.11.0)", "tox (>=3.7.0)", "pytest (>=2.8.0)", "pytest-pep8 (>=1.0.6)", "pytest-cov (>=1.8.0)", "pydocstyle (>=1.0.0)", "mock (>=1.3.0)", "isort (>=4.2.2)", "coverage (>=4.0)", "check-manifest (>=0.25)", "sphinx-rtd-theme (>=0.1.9)", "Sphinx (>=1.4.4)"]
 
 [[package]]
 name = "distlib"
@@ -511,10 +511,10 @@ six = ">=1.9"
 webencodings = "*"
 
 [package.extras]
-all = ["genshi", "chardet (>=2.2)", "lxml"]
-chardet = ["chardet (>=2.2)"]
-genshi = ["genshi"]
 lxml = ["lxml"]
+genshi = ["genshi"]
+chardet = ["chardet (>=2.2)"]
+all = ["lxml", "chardet (>=2.2)", "genshi"]
 
 [[package]]
 name = "identify"
@@ -543,6 +543,22 @@ category = "dev"
 optional = false
 python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
 
+[[package]]
+name = "importlib-metadata"
+version = "4.12.0"
+description = "Read metadata from Python packages"
+category = "dev"
+optional = false
+python-versions = ">=3.7"
+
+[package.dependencies]
+zipp = ">=0.5"
+
+[package.extras]
+docs = ["sphinx", "jaraco.packaging (>=9)", "rst.linker (>=1.9)"]
+perf = ["ipython"]
+testing = ["pytest (>=6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytest-cov", "pytest-enabler (>=1.3)", "packaging", "pyfakefs", "flufl.flake8", "pytest-perf (>=0.9.2)", "pytest-black (>=0.3.7)", "pytest-mypy (>=0.9.1)", "importlib-resources (>=1.3)"]
+
 [[package]]
 name = "iniconfig"
 version = "1.1.1"
@@ -607,7 +623,7 @@ colorama = {version = ">=0.3.4", markers = "sys_platform == \"win32\""}
 win32-setctime = {version = ">=1.0.0", markers = "sys_platform == \"win32\""}
 
 [package.extras]
-dev = ["codecov (>=2.0.15)", "colorama (>=0.3.4)", "flake8 (>=3.7.7)", "tox (>=3.9.0)", "tox-travis (>=0.12)", "pytest (>=4.6.2)", "pytest-cov (>=2.7.1)", "Sphinx (>=2.2.1)", "sphinx-autobuild (>=0.7.1)", "sphinx-rtd-theme (>=0.4.3)", "black (>=19.10b0)", "isort (>=5.1.1)"]
+dev = ["isort (>=5.1.1)", "black (>=19.10b0)", "sphinx-rtd-theme (>=0.4.3)", "sphinx-autobuild (>=0.7.1)", "Sphinx (>=2.2.1)", "pytest-cov (>=2.7.1)", "pytest (>=4.6.2)", "tox-travis (>=0.12)", "tox (>=3.9.0)", "flake8 (>=3.7.7)", "colorama (>=0.3.4)", "codecov (>=2.0.15)"]
 
 [[package]]
 name = "m2r"
@@ -1060,18 +1076,19 @@ python-versions = ">=3.6"
 
 [[package]]
 name = "sphinx"
-version = "3.5.2"
+version = "5.1.1"
 description = "Python documentation generator"
 category = "dev"
 optional = false
-python-versions = ">=3.5"
+python-versions = ">=3.6"
 
 [package.dependencies]
 alabaster = ">=0.7,<0.8"
 babel = ">=1.3"
 colorama = {version = ">=0.3.5", markers = "sys_platform == \"win32\""}
-docutils = ">=0.12"
+docutils = ">=0.14,<0.20"
 imagesize = "*"
+importlib-metadata = {version = ">=4.4", markers = "python_version < \"3.10\""}
 Jinja2 = ">=2.3"
 packaging = "*"
 Pygments = ">=2.0"
@@ -1079,15 +1096,15 @@ requests = ">=2.5.0"
 snowballstemmer = ">=1.1"
 sphinxcontrib-applehelp = "*"
 sphinxcontrib-devhelp = "*"
-sphinxcontrib-htmlhelp = "*"
+sphinxcontrib-htmlhelp = ">=2.0.0"
 sphinxcontrib-jsmath = "*"
 sphinxcontrib-qthelp = "*"
-sphinxcontrib-serializinghtml = "*"
+sphinxcontrib-serializinghtml = ">=1.1.5"
 
 [package.extras]
 docs = ["sphinxcontrib-websupport"]
-lint = ["flake8 (>=3.5.0)", "isort", "mypy (>=0.800)", "docutils-stubs"]
-test = ["pytest", "pytest-cov", "html5lib", "cython", "typed-ast"]
+lint = ["flake8 (>=3.5.0)", "flake8-comprehensions", "flake8-bugbear", "isort", "mypy (>=0.971)", "sphinx-lint", "docutils-stubs", "types-typed-ast", "types-requests"]
+test = ["pytest (>=4.6)", "html5lib", "cython", "typed-ast"]
 
 [[package]]
 name = "sphinx-autodoc-typehints"
@@ -1113,8 +1130,8 @@ optional = false
 python-versions = ">=3.5"
 
 [package.extras]
-lint = ["flake8", "mypy", "docutils-stubs"]
 test = ["pytest"]
+lint = ["docutils-stubs", "mypy", "flake8"]
 
 [[package]]
 name = "sphinxcontrib-devhelp"
@@ -1125,20 +1142,20 @@ optional = false
 python-versions = ">=3.5"
 
 [package.extras]
-lint = ["flake8", "mypy", "docutils-stubs"]
 test = ["pytest"]
+lint = ["docutils-stubs", "mypy", "flake8"]
 
 [[package]]
 name = "sphinxcontrib-htmlhelp"
-version = "1.0.3"
+version = "2.0.0"
 description = "sphinxcontrib-htmlhelp is a sphinx extension which renders HTML help files"
 category = "dev"
 optional = false
-python-versions = ">=3.5"
+python-versions = ">=3.6"
 
 [package.extras]
-lint = ["flake8", "mypy", "docutils-stubs"]
-test = ["pytest", "html5lib"]
+test = ["html5lib", "pytest"]
+lint = ["docutils-stubs", "mypy", "flake8"]
 
 [[package]]
 name = "sphinxcontrib-jsmath"
@@ -1149,7 +1166,7 @@ optional = false
 python-versions = ">=3.5"
 
 [package.extras]
-test = ["pytest", "flake8", "mypy"]
+test = ["mypy", "flake8", "pytest"]
 
 [[package]]
 name = "sphinxcontrib-qthelp"
@@ -1160,12 +1177,12 @@ optional = false
 python-versions = ">=3.5"
 
 [package.extras]
-lint = ["flake8", "mypy", "docutils-stubs"]
 test = ["pytest"]
+lint = ["docutils-stubs", "mypy", "flake8"]
 
 [[package]]
 name = "sphinxcontrib-serializinghtml"
-version = "1.1.4"
+version = "1.1.5"
 description = "sphinxcontrib-serializinghtml is a sphinx extension which outputs \"serialized\" HTML files (json and pickle)."
 category = "dev"
 optional = false
@@ -1338,7 +1355,7 @@ optional = false
 python-versions = ">=3.5"
 
 [package.extras]
-dev = ["pytest (>=4.6.2)", "black (>=19.3b0)"]
+dev = ["black (>=19.3b0)", "pytest (>=4.6.2)"]
 
 [[package]]
 name = "wrapt"
@@ -1348,10 +1365,22 @@ category = "dev"
 optional = false
 python-versions = "*"
 
+[[package]]
+name = "zipp"
+version = "3.8.1"
+description = "Backport of pathlib-compatible object wrapper for zip files"
+category = "dev"
+optional = false
+python-versions = ">=3.7"
+
+[package.extras]
+docs = ["sphinx", "jaraco.packaging (>=9)", "rst.linker (>=1.9)", "jaraco.tidelift (>=1.4)"]
+testing = ["pytest (>=6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytest-cov", "pytest-enabler (>=1.3)", "jaraco.itertools", "func-timeout", "pytest-black (>=0.3.7)", "pytest-mypy (>=0.9.1)"]
+
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.9"
-content-hash = "1a8e7e4fb91b4058d8e3c6292b092fd50f7963fea646172c45bcfe4749ef4b6c"
+content-hash = "f47148a6b09cb6b5d0e31bf712f5eadacf0436586799f6713117a31b5c0ec409"
 
 [metadata.files]
 alabaster = [
@@ -1597,6 +1626,10 @@ imagesize = [
     {file = "imagesize-1.2.0-py2.py3-none-any.whl", hash = "sha256:6965f19a6a2039c7d48bca7dba2473069ff854c36ae6f19d2cde309d998228a1"},
     {file = "imagesize-1.2.0.tar.gz", hash = "sha256:b1f6b5a4eab1f73479a50fb79fcf729514a900c341d8503d62a62dbc4127a2b1"},
 ]
+importlib-metadata = [
+    {file = "importlib_metadata-4.12.0-py3-none-any.whl", hash = "sha256:7401a975809ea1fdc658c3aa4f78cc2195a0e019c5cbc4c06122884e9ae80c23"},
+    {file = "importlib_metadata-4.12.0.tar.gz", hash = "sha256:637245b8bab2b6502fcbc752cc4b7a6f6243bb02b31c5c26156ad103d3d45670"},
+]
 iniconfig = [
     {file = "iniconfig-1.1.1-py2.py3-none-any.whl", hash = "sha256:011e24c64b7f47f6ebd835bb12a743f2fbe9a26d4cecaa7f53bc4f35ee9da8b3"},
     {file = "iniconfig-1.1.1.tar.gz", hash = "sha256:bc3af051d7d14b2ee5ef9969666def0cd1a000e121eaea580d4a313df4b37f32"},
@@ -1934,8 +1967,8 @@ soupsieve = [
     {file = "soupsieve-2.2.tar.gz", hash = "sha256:407fa1e8eb3458d1b5614df51d9651a1180ea5fedf07feb46e45d7e25e6d6cdd"},
 ]
 sphinx = [
-    {file = "Sphinx-3.5.2-py3-none-any.whl", hash = "sha256:ef64a814576f46ec7de06adf11b433a0d6049be007fefe7fd0d183d28b581fac"},
-    {file = "Sphinx-3.5.2.tar.gz", hash = "sha256:672cfcc24b6b69235c97c750cb190a44ecd72696b4452acaf75c2d9cc78ca5ff"},
+    {file = "Sphinx-5.1.1-py3-none-any.whl", hash = "sha256:309a8da80cb6da9f4713438e5b55861877d5d7976b69d87e336733637ea12693"},
+    {file = "Sphinx-5.1.1.tar.gz", hash = "sha256:ba3224a4e206e1fbdecf98a4fae4992ef9b24b85ebf7b584bb340156eaf08d89"},
 ]
 sphinx-autodoc-typehints = [
     {file = "sphinx-autodoc-typehints-1.11.1.tar.gz", hash = "sha256:244ba6d3e2fdb854622f643c7763d6f95b6886eba24bec28e86edf205e4ddb20"},
@@ -1950,8 +1983,8 @@ sphinxcontrib-devhelp = [
     {file = "sphinxcontrib_devhelp-1.0.2-py2.py3-none-any.whl", hash = "sha256:8165223f9a335cc1af7ffe1ed31d2871f325254c0423bc0c4c7cd1c1e4734a2e"},
 ]
 sphinxcontrib-htmlhelp = [
-    {file = "sphinxcontrib-htmlhelp-1.0.3.tar.gz", hash = "sha256:e8f5bb7e31b2dbb25b9cc435c8ab7a79787ebf7f906155729338f3156d93659b"},
-    {file = "sphinxcontrib_htmlhelp-1.0.3-py2.py3-none-any.whl", hash = "sha256:3c0bc24a2c41e340ac37c85ced6dafc879ab485c095b1d65d2461ac2f7cca86f"},
+    {file = "sphinxcontrib-htmlhelp-2.0.0.tar.gz", hash = "sha256:f5f8bb2d0d629f398bf47d0d69c07bc13b65f75a81ad9e2f71a63d4b7a2f6db2"},
+    {file = "sphinxcontrib_htmlhelp-2.0.0-py2.py3-none-any.whl", hash = "sha256:d412243dfb797ae3ec2b59eca0e52dac12e75a241bf0e4eb861e450d06c6ed07"},
 ]
 sphinxcontrib-jsmath = [
     {file = "sphinxcontrib-jsmath-1.0.1.tar.gz", hash = "sha256:a9925e4a4587247ed2191a22df5f6970656cb8ca2bd6284309578f2153e0c4b8"},
@@ -1962,8 +1995,8 @@ sphinxcontrib-qthelp = [
     {file = "sphinxcontrib_qthelp-1.0.3-py2.py3-none-any.whl", hash = "sha256:bd9fc24bcb748a8d51fd4ecaade681350aa63009a347a8c14e637895444dfab6"},
 ]
 sphinxcontrib-serializinghtml = [
-    {file = "sphinxcontrib-serializinghtml-1.1.4.tar.gz", hash = "sha256:eaa0eccc86e982a9b939b2b82d12cc5d013385ba5eadcc7e4fed23f4405f77bc"},
-    {file = "sphinxcontrib_serializinghtml-1.1.4-py2.py3-none-any.whl", hash = "sha256:f242a81d423f59617a8e5cf16f5d4d74e28ee9a66f9e5b637a18082991db5a9a"},
+    {file = "sphinxcontrib-serializinghtml-1.1.5.tar.gz", hash = "sha256:aa5f6de5dfdf809ef505c4895e51ef5c9eac17d0f287933eb49ec495280b6952"},
+    {file = "sphinxcontrib_serializinghtml-1.1.5-py2.py3-none-any.whl", hash = "sha256:352a9a00ae864471d3a7ead8d7d79f5fc0b57e8b3f95e9867eb9eb28999b92fd"},
 ]
 stevedore = [
     {file = "stevedore-3.3.0-py3-none-any.whl", hash = "sha256:50d7b78fbaf0d04cd62411188fa7eedcb03eb7f4c4b37005615ceebe582aa82a"},
@@ -2049,3 +2082,7 @@ win32-setctime = [
 wrapt = [
     {file = "wrapt-1.12.1.tar.gz", hash = "sha256:b62ffa81fb85f4332a4f609cab4ac40709470da05643a082ec1eb88e6d9b97d7"},
 ]
+zipp = [
+    {file = "zipp-3.8.1-py3-none-any.whl", hash = "sha256:47c40d7fe183a6f21403a199b3e4192cca5774656965b0a4988ad2f8feb5f009"},
+    {file = "zipp-3.8.1.tar.gz", hash = "sha256:05b45f1ee8f807d0cc928485ca40a07cb491cf092ff587c0df9cb1fd154848d2"},
+]
diff --git a/pyproject.toml b/pyproject.toml
index b433f89..0c0a38c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -61,7 +61,7 @@ pytest-cov = "^2.10"
 pytest-randomly = "^3.4"
 coverage = "^5.5"
 
-sphinx = "^3.5"
+sphinx = "^5.1"
 sphinx-autodoc-typehints = "^1.11"
 
 doc8 = "^0.8"