chore(docs): fixed readthedocs build (#50)

Author: RitvikKapila

.github/workflows/ci_tests.yaml

@@ -22,7 +22,7 @@ jobs:
           # x86 builds are only meaningful for Windows
           - os: windows-latest
             architecture: x86
-          - os: macos-latest
+          - os: macos-12
             architecture: x64
         major:
           - 3

.readthedocs.yaml

@@ -0,0 +1,27 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Set the OS, Python version and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.8"
+
+# Build documentation in the doc/ directory with Sphinx
+sphinx:
+   configuration: doc/conf.py
+
+# Don't need to build documentation for test vectors or any other
+# sub modules
+submodules:
+  exclude: all
+
+python:
+  install:
+    - requirements: doc/requirements.txt
+    - method: pip
+      path: .

src/base64io/__init__.py

@@ -154,7 +154,8 @@ def _passthrough_interactive_check(self, method_name, mode):
         except AttributeError:
             if (
                 _py2()
-                and isinstance(self.__wrapped, file)  # pylint: disable=isinstance-second-argument-not-valid-type
+                # pylint: disable=isinstance-second-argument-not-valid-type, possibly-used-before-assignment
+                and isinstance(self.__wrapped, file)
                 and mode in self.__wrapped.mode
             ):
                 return True