code: def char(self, c: str) -> None:
          
          if self.peek() == c:
              self.offset += 1
          else:
              raise UnexpectedInput(self, f"char '{c}'")
docs: Parse the specified character.
  
          Args:
              c: One-character string.
  
          Raises:
              EndOfInput: If past the end of `self.input`.
              UnexpectedInput: If the next character is different from `c`.