code: private boolean isAlleleCorrect(String allele, boolean acceptAmbiguousBases) {
          if (StringUtils.isNotEmpty(allele)) {
              for (char base : allele.toCharArray()) {
                  if (!isValidBase(base, acceptAmbiguousBases)) {
                      return false;
                  }
              }
          }
          return true;
      }
docs: Checks if all bases in the allele are valid bases.
  @param allele the reference bases
  @return