You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: selection.go
    path of file: ./repos/fo/types
    
    the code of the file until where you have to start completion: // Copyright 2013 The Go Authors. 
    
func (s *Selection) Type() Type {
	switch s.kind {
	case MethodVal:
		// The type of x.f is a method with its receiver type set
		// to the type of x.
		sig := *s.obj.(*Func).typ.(*Signature)
		recv := *sig.recv
		recv.typ = s.recv
		sig.recv = &recv
		return &sig

	case MethodExpr:
		// The type of x.f is a function (without receiver)
		// and an additional first argument with the same type as x.
		// TODO(gri) Similar code is already in call.go - factor!
		// TODO(gri) Compute this eagerly to avoid allocations.
		sig := *s.obj.(*Func).typ.(*Signature)
		arg0 := *sig.recv
		sig.recv = nil
		arg0.typ = s.recv
		var params []*Var
		if sig.params != nil {
			params = sig.params.vars
		}
		sig.params = NewTuple(append([]*Var{&arg0}, params...)...)
		return &sig
	}

	// In all other cases, the type of x.f is the type of x.
	return s.obj.Type()
}