Need type annotation for variable in python 3.5 code

If you are having blank value, you must define the type of variable. For example:

my_val: str = ""
my_val1: dict = {}
my_val2: list = []

etc. In your case, I will consider changing the version of python to 3.6 and update code is required.

Your code is confusing the type inference that mypy tries to do. For example, redefining a name as in the following snippet, doesn't allow mypy to deduce the type of f:

f = []
f = {}

Since it can't understand what the type of f is supposed to be, it complains and tells you that it needs an annotation for the variable. You can explicitly provide a type-hint with:

• A type comment for Python 3.5.
• A variable annotation for Python 3.6

mypy isn't compiling in 3.6, this error exists in both versions. The difference is in how you can tackle it.

Use comments to annotate variable type

x = 5  # type: int
my_list = []  # type: List[str]

Check cheat sheet

https://mypy.readthedocs.io/en/latest/cheat_sheet_py3.html