Some thing about source and sink connection

When a source src has multiple outputs we can connect as follows


fg.connect((src, 0),.......blocks of fg1)
fg.connect((src, 1),.......blocks of fg2)
fg.connect((src, 3),.......blocks of fg3)

or in other case 

fg.connect((src, 0),.......blocks of fg1)
fg.connect((src, 0),.......blocks of fg2)
fg.connect((src, 0),.......blocks of fg3)


This will connect output 0 to fg1 and output 1 to fg2 and so on

But when it has single output , we connect as 

fg.connect(src, fg1)
fg.connect(src, fg2)