code: def assert_trade_protocol(event):
      """Assert that an event meets the protocol for datasource TRADE outputs."""
      assert_datasource_protocol(event)
  
      assert event.type == DATASOURCE_TYPE.TRADE
      assert isinstance(event.price, numbers.Real)
      assert isinstance(event.volume, numbers.Integral)
      assert isinstance(event.dt, datetime)
  
file_path: catalyst/catalyst/gens/utils.py
imports: import pytz
  import numbers
  from hashlib import md5
  from datetime import datetime
  from catalyst.protocol import DATASOURCE_TYPE
  from six import iteritems, b
label_desc: Use image node_id 3 for calling a global function with example usage: assert_trade_protocol(event) without return types