code: def _get_max_size(assignment):
      if not assignment:
          return 0
      ret = max([x[1].size for x in assignment])
      ret = 0 if ret is None else ret
      return ret
  
imports: import networkx
  import collections
  import time
  import copy
  from caffe2.python import workspace, core
  from caffe2.proto import caffe2_pb2
  import enum
  import logging
  import caffe2.python._import_c_extension
label_desc: Use image node_id 18 for calling a global function with example usage: _get_max_size(assignment) and returns: ret, int