st = StartNode('a_pyflow_test')
op = OperationNode('do something')
cond = ConditionNode('Yes or No?')
io = InputOutputNode(InputOutputNode.OUTPUT, 'something...')
sub = SubroutineNode('A Subroutine')
e = EndNode('a_pyflow_test')
st.connect(op)
op.connect(cond)
cond.connect_yes(io)
cond.connect_no(sub)
sub.connect(op, "right") # sub->op line starts from the right of sub
io.connect(e)