code: def limit_string_length(string, max_len=50):
      """Limit the length of input string.
  
      Args:
        string: Input string.
        max_len: (int or None) If int, the length limit. If None, no limit.
  
      Returns:
        Possibly length-limited string.
      """
      if max_len is None or len(string) <= max_len:
          return string
      else:
          return "..." + string[len(string) - max_len :]
  
imports: import collections
  import threading
  import numpy
  from tensorflow.core.protobuf import debug_event_pb2
  from tensorflow.python.debug.lib import op_callbacks_common
  from tensorflow.python.debug.lib import source_utils
  from tensorflow.python.eager import monitoring
  from tensorflow.python.framework import op_callbacks
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_debug_ops
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.util import compat
  from tensorflow.python.util import object_identity
  from tensorflow.python.util.tf_export import tf_export
label_desc: Use image node_id 1 for calling a global function with example usage: limit_string_length(string, max_len) and returns: string, unknown