Travis build failures fix (#120)

Author: Shreyas-vgr

.gitignore

@@ -66,3 +66,8 @@ target/
 
 # IntelliJ configs
 *.iml
+.idea/
+
+# mypy cache
+.mypy_cache/
+

.travis.yml

@@ -30,9 +30,9 @@ matrix:
       env:
       - TOX_ENV=py37-mywin
       before_install:
-      - choco install python3
+      - choco install python3 --version 3.7.4
       - export PATH="/c/Python37:/c/Python37/Scripts:$PATH"
-      - set TRAVIS_PYTHON_VERSION='3.6'
+      - set TRAVIS_PYTHON_VERSION='3.7'
 install:
   - pip install --upgrade tox
 script:

ask-sdk-core/ask_sdk_core/serialize.py

@@ -59,7 +59,7 @@ class DefaultSerializer(Serializer):
     }
 
     def serialize(self, obj):  # type: ignore
-        # type: (Any) -> Union[Dict[str, Any], List, Tuple, str, int, float, None]
+        # type: (Any) -> Union[Dict[str, Any], List, Tuple, str, int, float, bytes, None]
         """Builds a serialized object.
 
         * If obj is None, return None.
@@ -79,7 +79,7 @@ def serialize(self, obj):  # type: ignore
         :param obj: The data to serialize.
         :type obj: object
         :return: The serialized form of data.
-        :rtype: Union[Dict[str, Any], List, Tuple, str, int, float, None]
+        :rtype: Union[Dict[str, Any], List, Tuple, str, int, float, bytes, None]
         """
         if obj is None:
             return None

tox.ini

@@ -49,7 +49,7 @@ setenv =
     AWS_DEFAULT_REGION = us-west-2
 commands =
     flake8 .
-    pip install --upgrade pip
+    #pip install --upgrade pip
     pip install --upgrade wheel
     python {toxinidir}\scripts\ci\sdk_install
     python {toxinidir}\scripts\ci\run_tests