keep_max_form creates a copy df using MultiIndex and remove_unused_le…

…vels() to get sliced data from feasibility table.

urbansim/developer/developer.py

@@ -62,13 +62,8 @@ def keep_form_with_max_profit(self, forms=None):
         f = self.feasibility
 
         if forms is not None:
-            feas = pd.DataFrame(index=f.index,
-                                columns=pd.MultiIndex.from_tuples(f[forms].columns.values))
-
-            for form in forms:
-                feas[form] = f[form].values
-
-            f = feas
+            f_index = f[forms].columns.remove_unused_levels()
+            f = pd.DataFrame(data=f[forms], columns=f_index)
 
         if len(f) > 0:
             mu = self._max_form(f, "max_profit")