aima/csp.py
def unassign(self, var, assignment):
        "Remove var from assignment (if it is there) and track conflicts."
        if var in assignment:
            self.record_conflict(assignment, var, assignment[var], -1)
        CSP.unassign(self, var, assignment)
def unassign(self, var, assignment):
        "Remove var from assignment (if it is there) and track conflicts."
        if var in assignment:
            self.record_conflict(assignment, var, assignment[var], -1)
        CSP.unassign(self, var, assignment)
Remove var from assignment (if it is there) and track conflicts.