Fixed illegal set addition
@@ -256,7 +256,7 @@ class CPM_template(SolverInterface):
:type cpm_con (list of) Expression(s)
"""
# add new user vars to the set
- self.user_vars += get_variables(cpm_con)
+ self.user_vars.update(set(get_variables(cpm_con)))
# apply transformations, then post internally
# XXX chose the transformations your solver needs, see cpmpy/transformations/
