code: def getValue(self):
      ret = None
      if self.windowFull():
          y = self.getValues()
          ret = lsreg(self.__x, y)[0]
      return ret
  
imports: from pyalgotrade import technical
  from pyalgotrade.utils import collections
  from pyalgotrade.utils import dt
  import numpy
  from scipy import stats
label_desc: Use image node_id 2 for calling the SlopeEventWindow obj's underlying member method code with example usage: obj.getValue() and returns: ret