class_docstr: Widget for displaying differences between hierarchical python data structures
  (eg, nested dicts, lists, and arrays)
docstr: Set the data to be compared in this widget.
code: def setData(self, a, b):
      """
      Set the data to be compared in this widget.
      """
      self.data = (a, b)
      self.trees[0].setData(a)
      self.trees[1].setData(b)
  
      return self.compare(a, b)
  
file_path: pyqtgraph/pyqtgraph/widgets/DiffTreeWidget.py
imports: import numpy
  from ..None import functions
  from ..Qt import QtWidgets
  from .DataTreeWidget import DataTreeWidget
label_desc: Use image node_id 2 for calling the DiffTreeWidget obj's underlying member method code with example usage: obj.setData(a, b) and returns: self