included

# File activesupport/lib/active_support/concern.rb, line 126
    def included(base = nil, &block)
      if base.nil?
        if instance_variable_defined?(:@_included_block)
          if @_included_block.source_location != block.source_location
            raise MultipleIncludedBlocks
          end
        else
          @_included_block = block
        end
      else
        super
      end
    end