def is_valid?
      result = false == is_blank?(@volume_id) &&
               false == is_blank?(@device_name) &&
               false == is_blank?(@volume_status) &&
               false == is_blank?(@mount_points) &&
               nil == @mount_points.find { |mount_point| is_blank?(mount_point) }
      return result
    end
def is_valid?
      result = false == is_blank?(@volume_id) &&
               false == is_blank?(@device_name) &&
               false == is_blank?(@volume_status) &&
               false == is_blank?(@mount_points) &&
               nil == @mount_points.find { |mount_point| is_blank?(mount_point) }
      return result
    end
Determines if this object is valid.

 === Return
 result(Boolean):: true if this object is valid, false if required fields are nil or empty