C.D. Reimer

While cleaning up code in my chess program that I’m writing in Python as a learning exercise, I came across yet another problem with the mypy static type checker. This time with the Enum.name attribute.

color = Color(self._color).name.capitalize()

The statement worked but mypy reported an error message.

error: Item “None” of “Optional[str]” has no attribute “capitalize”

I came up with a solution for that problem.

Read my essay and follow me on Medium. Your support is greatly appreciated.

The mypy static type checker always complain about using a dictionary to call functions. Especially this code segment from my chess program that I’m writing in Python as a learning exercise.

status = {Bishop: self.validate_move_bishop,
          King: self.validate_move_king,
          Knight: self.validate_move_knight,
          Pawn: self.validate_move_pawn,
          Queen: self.validate_move_queen,
          Rook: self.validate_move_rook,
         }.get(type(self._board[start]))(start, end)

This message, error: “None” not callable, always leave me cross-eyed at times. I came up with a solution for that problem.

Read my essay and follow me on Medium. Your support is greatly appreciated.

While cleaning up my code in a chess program that I’m writing in Python as a learning exercise, I created an Enum class to represent the starting ranks for certain pieces on the board. Since I wanted the Enum to also behave like a list, I added that to the class definition. The mypy static type checker reported an incompatible __hash__ dunder method error between list and Enum. I came up with a solution for that problem.

Read my essay and follow me on Medium. Your support is greatly appreciated.