def customer_id=(customer_id)

      if !customer_id.nil? && customer_id.to_s.length > 50
        fail ArgumentError, "invalid value for 'customer_id', the character length must be smaller than or equal to 50."
      end

      @customer_id = customer_id
    end
def customer_id=(customer_id)

      if !customer_id.nil? && customer_id.to_s.length > 50
        fail ArgumentError, "invalid value for 'customer_id', the character length must be smaller than or equal to 50."
      end

      @customer_id = customer_id
    end
Custom attribute writer method with validation
 @param [Object] customer_id Value to be assigned