def __repr__(self):
        return "<Requirement(package={package}, version='{version}')>".format(
            package=self.package, version=self.version)
def iqd_phasor(up, iqd, uqd, ax=0):
    """creates a phasor plot
    up: internal voltage
    iqd: current
    uqd: terminal voltage"""

    uxdq = (uqd[1]/np.sqrt(2), (uqd[0]/np.sqrt(2)-up))
    __phasor_plot(ax, up, (iqd[1]/np.sqrt(2), iqd[0]/np.sqrt(2)), uxdq)