Drop variant sequences which are shorter than request or don't have
    enough supporting reads.

def filter_variant_sequences(
        variant_sequences,
        preferred_sequence_length,
        min_variant_sequence_coverage=MIN_VARIANT_SEQUENCE_COVERAGE,):
    """
    Drop variant sequences which are shorter than request or don't have
    enough supporting reads.
    """
    variant_sequences = trim_variant_sequences(
        variant_sequences, min_variant_sequence_coverage)

    return filter_variant_sequences_by_length(
        variant_sequences=variant_sequences,
        preferred_sequence_length=preferred_sequence_length)