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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def display_hierarchy_helper(root, parent_id_to_children, depth):
 """Recursive helper for displaying the hierarchy. Args: root: The current root ad unit. parent_id_to_children: The overall map of parent ids to children. depth: The current depth. """

  print '%s%s (%s)' % ('%s+--' % ('|'.join(['  '] * depth)),
                       root['name'], root['id'])

  # Recurse for each child of this root that has children.
  for child in parent_id_to_children.get(root['id'], []):
    display_hierarchy_helper(child, parent_id_to_children, depth + 1)