code: def __init__(self):
      (
          ma1,
          ma2,
      ) = bt.ind.SMA(
          period=15
      ), bt.ind.SMA(period=50)
      self.signal_add(bt.signal.SIGNAL_LONG, bt.ind.CrossOver(ma1, ma2))
  
file_path: backtrader/samples/calmar/calmar-test.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import argparse
  import datetime
  import backtrader
label_desc: Use image node_id 1 to create a new St object from inherited base classes: bt with example: obj = St()