dict1	[]	['dict_src']	['join','t']
dict2	[]	['join']	['t']
dict_src	[]	[]	['dict1']
join	[]	['dict1']	['dict2','s','t']
s	[]	['join']	[]
t	[]	['dict1','dict2','join']	[]
=====
dict1	[]	['dict_src']	['join','t']
dict2	[]	['join']	[]
dict_src	[]	[]	['dict1']
join	[]	['dict1']	['dict2','s','t']
mv	[]	[]	[]
s	[]	['join']	['t']
t	['mv']	['dict1','join','s']	[]
dict1
dict2
dict_src
join
mv
s
t
OK
OK
OK
dict1	[]	['dict_src']	['join','t']
dict2	[]	['join']	[]
dict_src	[]	[]	['dict1']
join	[]	['dict1']	['dict2','s','t']
mv	[]	[]	[]
s	[]	['join']	['t']
t	['mv']	['dict1','join','s']	[]
OK
dict1	[]	['dict_src']	['join','t']
dict2	[]	['join']	[]
dict_src	[]	[]	['dict1']
join	[]	['dict1']	['dict2','s','t']
s	[]	['join']	['t']
t	[]	['dict1','join','s']	[]
=====
dict1	[]	['dict_src']	['join']
dict_src	[]	[]	['dict1']
join	[]	['dict1']	[]