<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_samples_line(klass, arr):
 """Peform additional check on samples line"""

        if len(arr) <= len(REQUIRE_NO_SAMPLE_HEADER):
            if tuple(arr) != REQUIRE_NO_SAMPLE_HEADER:
                raise exceptions.IncorrectVCFFormat(
                    "Sample header line indicates no sample but does not "
                    "equal required prefix {}".format("\t".join(REQUIRE_NO_SAMPLE_HEADER))
                )
        elif tuple(arr[: len(REQUIRE_SAMPLE_HEADER)]) != REQUIRE_SAMPLE_HEADER:
            raise exceptions.IncorrectVCFFormat(
                'Sample header line (starting with "#CHROM") does not '
                "start with required prefix {}".format("\t".join(REQUIRE_SAMPLE_HEADER))
            )