def complex(real=0.0, imag=0.0):
    """Form a complex number

    Args:
        real (float, optional): The real part. Defaults to 0.0.
        imag (float, optional): The imaginary part. Defaults to 0.0.
    """ 
    if imag == 0.0 and real == 0.0:
        return complex_zero
    ...