Check the input x is numerical or not.

        Examples:
            >>> MathClass.isnumerical('78')
            True
            >>> MathClass.isnumerical('1.e-5')
            True
            >>> MathClass.isnumerical(None)
            False
            >>> MathClass.isnumerical('a1.2')
            False
            >>> MathClass.isnumerical(['1.2'])
            False
            >>> MathClass.isnumerical(numpy.float64(1.2))
            True

def isnumerical(x):
        # type: (...) -> bool
        """Check the input x is numerical or not.

        Examples:
            >>> MathClass.isnumerical('78')
            True
            >>> MathClass.isnumerical('1.e-5')
            True
            >>> MathClass.isnumerical(None)
            False
            >>> MathClass.isnumerical('a1.2')
            False
            >>> MathClass.isnumerical(['1.2'])
            False
            >>> MathClass.isnumerical(numpy.float64(1.2))
            True

        """
        try:
            xx = float(x)
        except TypeError:
            return False
        except ValueError:
            return False
        except Exception:
            return False
        else:
            return True