'Returns this function as a complex coordinate.'

def as_real_imag(self, deep=True, **hints):

    from sympy import cos, sin
    if self.args[0].is_real:
        if deep:
            hints['complex'] = False
            return (self.expand(deep, **hints), S.Zero)
        else:
            return (self, S.Zero)
    if deep:
        (re, im) = self.args[0].expand(deep, **hints).as_real_imag()
    else:
        (re, im) = self.args[0].as_real_imag()
    return ((sinh(re) * cos(im)), (cosh(re) * sin(im)))
