code: def create_data_map(msgs_to_read):
      '''
      Create a data map for usage when parsing the bag
      '''
      dmap = {}
      for topic in msgs_to_read.keys():
          base_name = get_key_name(topic) + '__'
          fields = {}
          for f in msgs_to_read[topic]:
              key = (base_name + f).replace('.', '_')
              fields[f] = key
          dmap[topic] = fields
      return dmaf create_data_map(msgs_to_read):
      '''
      Create a data map for usage when parsing the bag
      '''
      dmap = {}
      for topic in msgs_to_read.keys():
          base_name = get_key_name(topic) + '__'
          fields = {}
          for f in msgs_to_read[topic]:
              key = (base_name + f).replace('.', '_')
              fields[f] = key
          dmap[topic] = fields
      return dmap
docs: Create a data map for usage when parsing the bag