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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 _AddFieldPaths(node, prefix, field_mask):
 """Adds the field paths descended from node to field_mask."""

  if not node:
    field_mask.paths.append(prefix)
    return
  for name in sorted(node):
    if prefix:
      child_path = prefix + '.' + name
    else:
      child_path = name
    _AddFieldPaths(node[name], child_path, field_mask)