code: public Collection<Argument> getArguments(final String key) {
          final Collection<Argument> args = map.get(key);
          if (args != null) {
              return new ArrayList<>(args);
          }
          return Collections.emptyList();
      }
docs: Gets the value for the key.
  
  @param key the key to check for the value
  
  @return the value or an empty collection if no values were set