docs: def is_fp_arg(self, arg):
          """
          This should take a SimFunctionArgument instance and return whether or not that argument is a floating-point
          argument.
  
          Returns True for MUST be a floating point arg,
                  False for MUST NOT be a floating point arg,
                  None for when it can be either.
          """
          if arg in self.int_args:
              return False
          if arg in self.fp_args or arg == self.FP_RETURN_VAL:
              return True
          return None