docstr: A proxy-call to the dataframe's `.cov()`.
code: def cov(self):
      """
      A proxy-call to the dataframe's `.cov()`.
      """
      return self.dataframe.cov()
  
imports: from abc import ABC
label_desc: Use image node_id 39 for calling the DataframeAbstract obj's underlying member method code with example usage: obj.cov() and returns: self