def add_external_output_coupling(child, output_port = nil, child_port = nil)
      child = fetch_child(child) unless child.is_a?(Model)

      if !output_port.nil? && !child_port.nil?
        output_port = find_or_create_output_port_if_necessary(output_port)
        child_port = child.find_or_create_output_port_if_necessary(child_port)

        _output_couplings[child_port] << output_port
      end
    end
def add_external_output_coupling(child, output_port = nil, child_port = nil)
      child = fetch_child(child) unless child.is_a?(Model)

      if !output_port.nil? && !child_port.nil?
        output_port = find_or_create_output_port_if_necessary(output_port)
        child_port = child.find_or_create_output_port_if_necessary(child_port)

        _output_couplings[child_port] << output_port
      end
    end
@deprecated Use {#attach_output} or {#attach} instead.
 Adds an external output coupling (EOC) to self. Establish a relation
 between an output {Port} of one of self's children and one of self's
 output ports.

 If the ports aren't provided, they will be automatically generated.

 @param child [Model, String, Symbol] the child or its name
 @param output_port [Port, String, Symbol] specify the self output port or
   its name to connect to the child_port.
 @param child_port [Port, String, Symbol] specify the child's output port
   or its name.