<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def _get_raw(source, bitarray):
        ''' Get raw data as integer, based on offset and size '''
        offset = int(source['offset'])
        size = int(source['size'])
        return int(''.join(['1' if digit else '0' for digit in bitarray[offset:offset + size]]), 2)