def poly_np(x, *coefs):
    """
    f(x) = a * x + b * x**2 + c * x**3 + ...

    *args = (x, a, b, ...)
    """

    # Add a warning for something potentially incorrect
    if len(coefs) == 0:
        raise Exception("You have not provided any polynomial coefficients.")

    # Calculate using a loop
    result = x * 0
    for power,c in enumerate(coefs):
        result += c * (x ** (power+1))

    return result