docstr: A proxy-call to the dataframe's `.set_index()`.
code: def set_index(self, keys):
      """
      A proxy-call to the dataframe's `.set_index()`.
      """
      return self.dataframe.set_index(keys=keys)
  
imports: from abc import ABC
label_desc: Use image node_id 5 for calling the DataframeAbstract obj's underlying member method code with example usage: obj.set_index(keys) and returns: self