# File lib/sawyer/relation.rb, line 258
    def call(data = nil, options = nil)
      m = options && options[:method]
      if m && !@agent.allow_undefined_methods? && !@available_methods.include?(m == :head ? :get : m)
        raise ArgumentError, "method #{m.inspect} is not available: #{@available_methods.to_a.inspect}"
      end

      @agent.call m || @method, @href_template, data, options
    end