are_mergeable 0 0 FALSE
are_mergeable 0 2 FALSE
are_mergeable 0 1 TRUE
are_mergeable 1 0 TRUE
#
are_mergeable 4 4 FALSE
are_mergeable 4 6 FALSE
are_mergeable 4 5 TRUE
are_mergeable 5 4 TRUE
#
merge 4 5 7
