def to_hash
      hash = {}
      attributes = self.class.attribute_map.sort_by {|key,value| key}
      attributes.each { |attr, param|
        value = self.send(attr)
        next if value.nil?
        if value.is_a?(Array)
          hash[param] = value.compact.map{ |v| _to_hash(v) }
        else
          hash[param] = _to_hash(value)
        end
      }
      hash
    end
def to_hash
      hash = {}
      attributes = self.class.attribute_map.sort_by {|key,value| key}
      attributes.each { |attr, param|
        value = self.send(attr)
        next if value.nil?
        if value.is_a?(Array)
          hash[param] = value.compact.map{ |v| _to_hash(v) }
        else
          hash[param] = _to_hash(value)
        end
      }
      hash
    end
return the object in the form of hash