def root_locus_map(sysdata, gains=None):
    """Compute the root locus map for an LTI system.

    Calculate the root locus by finding the roots of 1 + k * G(s) where G
    is a linear system with transfer function num(s)/den(s) and each k is
    an element of kvect.

    Parameters
    ----------
    sys : LTI system or list of LTI systems
        Linear input/output systems (SISO only, for now).
    kvect : array_like, optional
        Gains to use in computing plot of closed-loop poles.
    ...
    """