def period_range(start=None, end=None, periods=None, freq='D', name=None):
 return PeriodIndex(start=start, end=end, periods=periods, freq=freq, name=name)

def period_range ( start = None , end = None , periods = None , freq = 'D' , name = None ) : return PeriodIndex ( start = start , end = end , periods = periods , freq = freq , name = name )
return a fixed frequency datetime index .