Change order of cases in Partitions to put cheaper tests first

src/sage/combinat/partition.py

@@ -5812,26 +5812,7 @@ def __classcall_private__(cls, n=None, **kwargs):
         """
         if n == infinity:
             raise ValueError("n cannot be infinite")
-        if n is None or n is NN or n is NonNegativeIntegers():
-            if len(kwargs) > 0:
-                if len(kwargs) == 1:
-                    if 'max_part' in kwargs:
-                        return Partitions_all_bounded(kwargs['max_part'])
-                    if 'regular' in kwargs:
-                        return RegularPartitions_all(kwargs['regular'])
-                    if 'restricted' in kwargs:
-                        return RestrictedPartitions_all(kwargs['restricted'])
-                elif len(kwargs) == 2:
-                    if 'regular' in kwargs:
-                        if kwargs['regular'] < 1 or kwargs['regular'] not in ZZ:
-                            raise ValueError("the regularity must be a positive integer")
-                        if 'max_part' in kwargs:
-                            return RegularPartitions_bounded(kwargs['regular'], kwargs['max_part'])
-                        if 'max_length' in kwargs:
-                            return RegularPartitions_truncated(kwargs['regular'], kwargs['max_length'])
-                raise ValueError("the size must be specified with any keyword argument")
-            return Partitions_all()
-        elif isinstance(n, (int,Integer)):
+        if isinstance(n, (int,Integer)):
             if len(kwargs) == 0:
                 return Partitions_n(n)
 
@@ -5885,6 +5866,25 @@ def __classcall_private__(cls, n=None, **kwargs):
                                            kwargs.get('min_length',0))
                 del kwargs['inner']
             return Partitions_with_constraints(n, **kwargs)
+        elif n is None or n is NN or n is NonNegativeIntegers():
+            if len(kwargs) > 0:
+                if len(kwargs) == 1:
+                    if 'max_part' in kwargs:
+                        return Partitions_all_bounded(kwargs['max_part'])
+                    if 'regular' in kwargs:
+                        return RegularPartitions_all(kwargs['regular'])
+                    if 'restricted' in kwargs:
+                        return RestrictedPartitions_all(kwargs['restricted'])
+                elif len(kwargs) == 2:
+                    if 'regular' in kwargs:
+                        if kwargs['regular'] < 1 or kwargs['regular'] not in ZZ:
+                            raise ValueError("the regularity must be a positive integer")
+                        if 'max_part' in kwargs:
+                            return RegularPartitions_bounded(kwargs['regular'], kwargs['max_part'])
+                        if 'max_length' in kwargs:
+                            return RegularPartitions_truncated(kwargs['regular'], kwargs['max_length'])
+                raise ValueError("the size must be specified with any keyword argument")
+            return Partitions_all()
 
         raise ValueError("n must be an integer or be equal to one of "
                          "None, NN, NonNegativeIntegers()")