code: def trim_variant_sequences(variant_sequences, min_variant_sequence_coverage):
      
      n_total = len(variant_sequences)
      trimmed_variant_sequences = [
          variant_sequence.trim_by_coverage(min_variant_sequence_coverage)
          for variant_sequence in variant_sequences
      ]
      collapsed_variant_sequences = collapse_substrings(trimmed_variant_sequences)
      n_after_trimming = len(collapsed_variant_sequences)
      logger.info(
          "Kept %d/%d variant sequences after read coverage trimming to >=%dx",
          n_after_trimming,
          n_total,
          min_variant_sequence_coverage)
      return collapsed_variant_sequences
docs: Trim VariantSequences to desired coverage and then combine any
      subsequences which get generated.