def type_cast(values)
      # Force into an array and run type_cast on each element.
      [values].flatten.compact.map { |value| __getobj__.type_cast(value) }
    end
def type_cast(values)
      # Force into an array and run type_cast on each element.
      [values].flatten.compact.map { |value| __getobj__.type_cast(value) }
    end
Wraps a Field object and typecasts/builds
 item as an array of the given field.