code: def lbrother(self):
      n = None
      if self.parent:
          for node in self.parent.children:
              if node == self:
                  return n
              else:
                  n = node
      return n
  
file_path: scikit-learn/sklearn/tree/_reingold_tilford.py
imports: import numpy
label_desc: Use image node_id 4 for calling the DrawTree obj's underlying member method code with example usage: obj.lbrother() and returns: n, n