class_docstr: Weighted Moving Average filter.
  
  :param dataSeries: The DataSeries instance being filtered.
  :type dataSeries: :class:`pyalgotrade.dataseries.DataSeries`.
  :param weights: A list of int/float with the weights.
  :type weights: list.
  :param maxLen: The maximum number of values to hold.
      Once a bounded length is full, when new items are added, a corresponding number of items are discarded from the
      opposite end. If None then dataseries.DEFAULT_MAX_LEN is used.
  :type maxLen: int.
code: def __init__(self, dataSeries, weights, maxLen=None):
      super(WMA, self).__init__(
          dataSeries, WMAEventWindow(weights), maxLen
      )
  
imports: import numpy
  from pyalgotrade import technical
label_desc: Use image node_id 1 to create a new WMA object from inherited base classes: technical with example: obj = WMA(dataSeries, weights, maxLen)