<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _resolve_dut_count(self):
 """ Calculates total amount of resources required and their types. :return: Nothing, modifies _dut_count, _hardware_count and _process_count :raises: ValueError if total count does not match counts of types separately. """

        self._dut_count = len(self._dut_requirements)
        self._resolve_process_count()
        self._resolve_hardware_count()
        if self._dut_count != self._hardware_count + self._process_count:
            raise ValueError("Missing or invalid type fields in dut configuration!")