code: public String get(final String key) {
          final Collection<Argument> args = map.get(key);
          if (args != null) {
              return args.iterator().hasNext() ? args.iterator().next().getValue() : null;
          }
          return null;
      }
docs: Gets the first value for the key.
  
  @param key the key to check for the value
  
  @return the value or {@code null} if the key is not found or the value was {@code null}