Call sympy_init in all added _sympy_ methods

src/sage/categories/sets_cat.py

@@ -2451,6 +2451,8 @@ def _sympy_(self):
                     True
                 """
                 from sympy import ProductSet
+                from sage.interfaces.sympy import sympy_init
+                sympy_init()
                 return ProductSet(*self.cartesian_factors())
 
         class ElementMethods:

src/sage/modules/free_module.py

@@ -5318,6 +5318,8 @@ def _sympy_(self):
             True
         """
         from sympy import ProductSet
+        from sage.interfaces.sympy import sympy_init
+        sympy_init()
         return ProductSet(*([self.coordinate_ring()] * self.rank()))
 
 

src/sage/rings/integer_ring.pyx

@@ -1477,6 +1477,8 @@ cdef class IntegerRing_class(PrincipalIdealDomain):
             Integers
         """
         from sympy import Integers
+        from sage.interfaces.sympy import sympy_init
+        sympy_init()
         return Integers
 
     def _sage_input_(self, sib, coerced):

src/sage/rings/rational_field.py

@@ -1586,6 +1586,8 @@ def _sympy_(self):
             Rationals
         """
         from sympy import Rationals
+        from sage.interfaces.sympy import sympy_init
+        sympy_init()
         return Rationals
 
     def _sage_input_(self, sib, coerced):

src/sage/sets/non_negative_integers.py

@@ -233,4 +233,6 @@ def _sympy_(self):
             Naturals0
         """
         from sympy import Naturals0
+        from sage.interfaces.sympy import sympy_init
+        sympy_init()
         return Naturals0

src/sage/sets/positive_integers.py

@@ -86,4 +86,6 @@ def _sympy_(self):
             Naturals
         """
         from sympy import Naturals
+        from sage.interfaces.sympy import sympy_init
+        sympy_init()
         return Naturals

src/sage/sets/real_set.py

@@ -433,6 +433,8 @@ def _sympy_(self):
             Interval.open(0, oo)
         """
         from sympy import Interval
+        from sage.interfaces.sympy import sympy_init
+        sympy_init()
         return Interval(self.lower(), self.upper(),
                         left_open=not self._lower_closed,
                         right_open=not self._upper_closed)
@@ -1869,6 +1871,8 @@ def _sympy_(self):
             False
         """
         from sympy import Reals, Union
+        from sage.interfaces.sympy import sympy_init
+        sympy_init()
         if self.is_universe():
             return Reals
         else: