code: def default(self, obj):
      if isinstance(obj, pd.Timestamp):
          return obj.strftime(DATE_TIME_FORMAT)
  
      # Let the base class default method raise the TypeError
      return JSONEncoder.default(self, obj)
  
file_path: catalyst/catalyst/exchange/utils/serialization_utils.py
imports: import json
  import re
  from json import JSONEncoder
  import pandas
  from catalyst.constants import DATE_TIME_FORMAT
  from six import string_types
label_desc: Use image node_id 1 for calling the ExchangeJSONEncoder obj's underlying member method code with example usage: obj.default(obj) and returns: JSONEncoder, obj