class_docstr: Moving Average Convergence-Divergence indicator as described in http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:moving_average_convergence_divergence_macd.
  
  :param dataSeries: The DataSeries instance being filtered.
  :type dataSeries: :class:`pyalgotrade.dataseries.DataSeries`.
  :param fastEMA: The number of values to use to calculate the fast EMA.
  :type fastEMA: int.
  :param slowEMA: The number of values to use to calculate the slow EMA.
  :type slowEMA: int.
  :param signalEMA: The number of values to use to calculate the signal EMA.
  :type signalEMA: int.
  :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.
docstr: Returns a :class:`pyalgotrade.dataseries.DataSeries` with the histogram (the difference between the MACD and the Signal).
docstr_tok: ["Returns","a",":","class",":","`","pyalgotrade.dataseries.DataSeries","`","with","the","histogram","(","the","difference","between","the","MACD","and","the","Signal",")","."]
code: def getHistogram(self):
      """Returns a :class:`pyalgotrade.dataseries.DataSeries` with the histogram (the difference between the MACD and the Signal)."""
      return self.__histogram
  
file_path: pyalgotrade/pyalgotrade/technical/macd.py
imports: from pyalgotrade.technical import ma
  from pyalgotrade import dataseries
label_desc: Use image node_id 3 for calling the MACD obj's underlying member method code with example usage: obj.getHistogram() and returns: self