'Mark every weekday in *byweekday*; *byweekday* can be a number or
sequence.
Elements of *byweekday* must be one of MO, TU, WE, TH, FR, SA,
SU, the constants from :mod:`dateutil.rrule`, which have been
imported into the :mod:`matplotlib.dates` namespace.
*interval* specifies the number of weeks to skip.  For example,
``interval=2`` plots every second week.'

def __init__(self, byweekday=1, interval=1, tz=None):

    if isinstance(byweekday, np.ndarray):
        [x.item() for x in byweekday.astype(int)]
    rule = rrulewrapper(DAILY, byweekday=byweekday, interval=interval, **self.hms0d)
    RRuleLocator.__init__(self, rule, tz)
