docstr: Serializes this instance to a JSON string.
docstr_tok: ["Serializes","this","instance","to","a","JSON","string","."]
code: def to_json_string(self, keep_none=False):
      """Serializes this instance to a JSON string."""
      data = {}
      for key in self.all_keys:
          value = getattr(self, key)
          if isinstance(value, paddle.Tensor):
              data[key] = value.detach().cpu().tolist()
          elif value is None and keep_none:
              data[key] = None
          else:
              data[key] = value
      return json.dumps(data) + "\n"
  
imports: import copy
  import json
  import pickle
  from typing import *
  import paddle
label_desc: Use image node_id 10 for calling the InputFeatures obj's underlying member method code with example usage: obj.to_json_string(keep_none) and returns: unknown