class_docstr: Moving Average Convergence Divergence. Defined by Gerald Appel in the 70s.
  
  It measures the distance of a short and a long term moving average to
  try to identify the trend.
  
  A second lagging moving average over the convergence-divergence should
  provide a "signal" upon being crossed by the macd
  
  Formula:
    - macd = ema(data, me1_period) - ema(data, me2_period)
    - signal = ema(macd, signal_period)
  
  See:
    - http://en.wikipedia.org/wiki/MACD
code: def _plotlabel(self):
      plabels = super(MACD, self)._plotlabel()
      if self.p.isdefault("movav"):
          plabels.remove(self.p.movav)
      return plabels
  
file_path: backtrader/backtrader/indicators/macd.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from .None import Indicator, MovAv
label_desc: Use image node_id 1 for calling the MACD obj's underlying member method code with example usage: obj._plotlabel() and returns: plabels