'This method reads the value from (location_a, location_b), checking it\'s
type and making sure only one is stored at that address.
Similar to raw_read, but checking types.
:see: https://github.com/andresriancho/w3af/issues/3955'

@requires_setup
def get_one(self, location_a, location_b):

    location_a = self._get_real_name(location_a)
    result = self.get(location_a, location_b, check_types=True)
    if (len(result) > 1):
        msg = 'Incorrect    use    of    get_one(),    found    %s    results.'
        raise RuntimeError((msg % result))
    elif (len(result) == 0):
        return []
    else:
        return result[0]
