diff --git a/.isort.cfg b/.isort.cfg
index 043be517..6154c80f 100644
--- a/.isort.cfg
+++ b/.isort.cfg
@@ -4,5 +4,5 @@ include_trailing_comma=True
 force_grid_wrap=0
 use_parentheses=True
 line_length=88
-known_third_party=deprecated,httpretty,jwt,requests,setuptools,urllib3
+known_third_party=deprecated,httpretty,jwt,pytest,requests,setuptools,urllib3
 known_first_party=github
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 84d3cbae..36c7c1ad 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -16,8 +16,3 @@ repos:
     rev: 3.7.9
     hooks:
       - id: flake8
-  - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v2.3.0
-    hooks:
-      - id: end-of-file-fixer
-      - id: trailing-whitespace
diff --git a/.travis.yml b/.travis.yml
index 9b9c91bf..5da9640d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,7 @@
 language: python
 matrix:
   include:
+    - env: TOXENV=lint
     - python: 3.5
       env: TOXENV=py35
     - python: 3.6
@@ -9,9 +10,7 @@ matrix:
       env: TOXENV=py37
     - python: 3.8
       env: TOXENV=py38
-    - env: TOXENV=flake8
-    - env: TOXENV=isort
-    - env: TOXENV=black
+    - env: TOXENV=docs
 install:
   - pip install tox
 script:
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 91799093..235cd0db 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -29,7 +29,7 @@ PyGithub adopts the black coding style and uses isort to sort imports.
 
 To manually format the code:
 ```
-tox -e format
+tox -e lint
 ```
 
 ## Pre-commit plugin
@@ -106,7 +106,7 @@ You may also want to investigate `tox` to run tests:
 
 ```
 pip install tox
-tox -epy36,flake8,black,isort
+tox -epy36
 ```
 
 ## Build documentation locally
diff --git a/github/GithubException.pyi b/github/GithubException.pyi
index ff70e5b0..ffb91bd0 100644
--- a/github/GithubException.pyi
+++ b/github/GithubException.pyi
@@ -33,3 +33,11 @@ class GithubException:
     def data(self) -> Dict[str, Union[str, List[str], List[Dict[str, str]]]]: ...
     @property
     def status(self) -> int: ...
+
+class IncompletableObject:
+    def __init__(self, status: Union[int, str], data: Any,) -> None: ...
+    def __str__(self) -> str: ...
+    @property
+    def data(self) -> Dict[str, Union[str, List[str], List[Dict[str, str]]]]: ...
+    @property
+    def status(self) -> int: ...
diff --git a/tests/Connection.py b/tests/Connection.py
index e2cd218c..6f7f878f 100644
--- a/tests/Connection.py
+++ b/tests/Connection.py
@@ -27,9 +27,8 @@ import itertools
 from io import StringIO
 from unittest.mock import Mock
 
-import httpretty
-
-import pytest
+import httpretty  # type: ignore
+import pytest  # type: ignore
 
 from . import Framework
 
diff --git a/tests/Retry.py b/tests/Retry.py
index a3a21e0e..87034e2f 100644
--- a/tests/Retry.py
+++ b/tests/Retry.py
@@ -27,8 +27,8 @@
 ################################################################################
 
 import requests
-import urllib3
-from httpretty import httpretty
+import urllib3  # type: ignore
+from httpretty import httpretty  # type: ignore
 
 import github
 
diff --git a/tox.ini b/tox.ini
index 83e104ea..2b57cc78 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,41 +1,24 @@
 [tox]
 envlist =
+    lint,
     py{35,36,37,38},
-    flake8,
-    isort,
-    black
+    docs
 
 [testenv]
 deps = -rtest-requirements.txt
 commands = pytest --cov=github {posargs}
 
-[testenv:flake8]
-basepython = python3.6
-skip_install = true
-deps = flake8
-commands = flake8 github tests scripts setup.py
-
-[testenv:isort]
-basepython = python3.6
-skip_install = true
-deps = isort
-commands = isort --check -rc github tests scripts setup.py
-
-[testenv:black]
-basepython = python3.6
-skip_install = true
-deps = black
-commands = black --check --diff github tests scripts setup.py
-
-[testenv:format]
+[testenv:lint]
 basepython = python3.6
 skip_install = true
 deps =
-    black
-    isort
+    pre-commit
+    mypy
 commands =
-    isort -rc github tests scripts setup.py
-    black github tests scripts setup.py
+    pre-commit run --all-files --show-diff-on-failure
+    ; Run mypy outside pre-commit because pre-commit runs mypy in a venv
+    ; that doesn't have dependencies or their type annotations installed.
+    mypy github/ tests/
 
 [testenv:docs]
 basepython = python3.6