code: def convert_datetimes_to_timestamps(data, datetime_attrs):
      
      if not data:
          return data
  
      new_data = {}
      for key, value in data.items():
          if key in datetime_attrs and isinstance(value, datetime):
              new_key = datetime_attrs[key]
              new_data[new_key] = timestamp_from_dt(value)
          else:
              new_data[key] = value
  
      return new_data
docs: Given a dictionary of data, and a dictionary of datetime attributes,
      return a new dictionary that converts any datetime attributes that may
      be present to their timestamped equivalent.