@staticmethod
def _eval_if_not_number(v, feed_dict):
    """ If v is not float (i.e. v is :class:`Express`), returns an evaluated value.

        Args:
            v (float/int/:class:`Coefficient`):
                The value to be evaluated.
            feed_dict (dict[str, float]):
                The value of :class:`Placeholder`.

        Returns:
            float: Evaluated value of the input :obj:`v`:
        """
    if isinstance(v, float) or isinstance(v, int):
        return v
    else:
        return v.evaluate(feed_dict)
