<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _CalculateElementsDataSize(self, context):
 """Calculates the elements data size. Args: context (Optional[DataTypeMapContext]):
 data type map context, used to determine the size hint. Returns: int: the elements data size or None if not available. """

    elements_data_size = None

    if self._HasElementsDataSize():
      elements_data_size = self._EvaluateElementsDataSize(context)

    elif self._HasNumberOfElements():
      element_byte_size = self._element_data_type_definition.GetByteSize()
      if element_byte_size is not None:
        number_of_elements = self._EvaluateNumberOfElements(context)
        elements_data_size = number_of_elements * element_byte_size

    return elements_data_size