code: def append_name(name, postfix):
      if name is None:
          return None
      elif name == "":
          return postfix
      else:
          return "%s_%s" % (name, postfix)
  
imports: from __future__ import division
  from __future__ import absolute_import
  from __future__ import print_function
  from __future__ import unicode_literals
  import logging
  import paddle.fluid.dygraph
  import paddle.fluid
  import paddle.fluid.layers
label_desc: Use image node_id 3 for calling a global function with example usage: append_name(name, postfix) and returns: None, postfix, unknown