code: public Optional<Boolean> getBoolean(String key) {
          Objects.requireNonNull(key, Required.KEY.toString());
  
          String value = this.values.get(key);
          if (StringUtils.isNotBlank(value)) {
              if (("1").equals(value)) {
                  return Optional.of(Boolean.TRUE);
              } else if (("true").equals(value)) {
                  return Optional.of(Boolean.TRUE);
              } else if (("false").equals(value)) {
                  return Optional.of(Boolean.FALSE);
              } else if (("0").equals(value)) {
                  return Optional.of(Boolean.FALSE);
              } else {
                  // Ignore anything else
              }
          }
  
          return Optional.empty();
      }
docs: Retrieves an optional boolean value corresponding to the name of the form element
  
  0 maps to false
  1 maps to true
  "true" maps to true
  "false" maps to false
  
  @param key The name of the form element
  @return Optional of Boolean