<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _check_constant_value_data(self, data):
 """Verify that the HDU's data is a constant value array."""


        arrayval = data.flat[0]
        if np.all(data == arrayval):
            return arrayval
        return None