code: protected void setValueInternal(String argument, char separator, GenericType<?> propertyType) {
  
      if (this.valueAlreadySet) {
        CliOptionDuplicateException exception = new CliOptionDuplicateException(getParameterContainer().getName());
        CliStyleHandling.EXCEPTION.handle(getLogger(), exception);
      }
      // TODO: separator currently ignored!
      Object value = getDependencies().getConverter().convertValue(argument, getParameterContainer(),
          propertyType.getAssignmentClass(), propertyType);
      setValueInternal(value);
      this.valueAlreadySet = true;
    }
docs: This method parses container value as from a single argument and sets it as new object.
  
  @param argument is the argument representing the container as string.
  @param separator is the character used as separator for the container values.
  @param propertyType is the {@link GenericType} of the property.