code: def is_source_key(key):
      src_regex = re.compile(r".+src$")
      if src_regex.match(key) is not None:
          return True
      else:
          return False
  
file_path: plotly.py/packages/python/chart-studio/chart_studio/utils.py
imports: from __future__ import absolute_import
  import os.path
  import re
  import threading
  import warnings
  import json
  from _plotly_utils.exceptions import PlotlyError
  from _plotly_utils.optional_imports import get_module
label_desc: Use image node_id 6 for calling a global function with example usage: is_source_key(key) and returns: True, False