+| | ... | This keyword also sets a test variable \${resetter}
+| | ... | to hold a callable which resets VPP state.
+| | ... | Keywords performing search will call it to get consistent trials.
+| | ... | Tests which do not wish to reset NAT state should use ramp-up,
+| | ... | so the resetter is not set if \${ramp_up_duration} variable
+| | ... | is (defined and) nonzero.
+| |
+| | ... | *Test variables read:*
+| | ... | - n_sessions - Expected number of opened sessions.
+| |