keep rep consistent with domain

sympy/polys/polyclasses.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from sympy.external.gmpy import GROUND_TYPES
+from sympy.external.gmpy import GROUND_TYPES, MPQ
 
 from sympy.utilities.exceptions import sympy_deprecation_warning
 
@@ -1241,6 +1241,10 @@ def _new(cls, rep, dom, lev):
         obj._rep = rep
         obj.lev = lev
         obj.dom = dom
+        if dom == ZZ and any(isinstance(i, MPQ) for i in rep):
+            raise ValueError('rep should not be MPQ when domain is ZZ')
+        if dom == QQ and not all(isinstance(i, MPQ) for i in rep):
+            raise ValueError('rep should be MPQ when domain is QQ')
         return obj
 
     def _strict_eq(f, g):

sympy/polys/tests/test_polyclasses.py

@@ -2,10 +2,11 @@
 
 from sympy.functions.elementary.miscellaneous import sqrt
 from sympy.polys.domains import ZZ, QQ
-from sympy.polys.polyclasses import DMP, DMF, ANP
+from sympy.polys.polyclasses import DMP, DMF, ANP, DMP_Python
 from sympy.polys.polyerrors import (CoercionFailed, ExactQuotientFailed,
                                     NotInvertible)
 from sympy.polys.specialpolys import f_polys
+from sympy.external.gmpy import MPQ
 from sympy.testing.pytest import raises, warns_deprecated_sympy
 
 f_0, f_1, f_2, f_3, f_4, f_5, f_6 = [ f.to_dense() for f in f_polys() ]
@@ -29,6 +30,14 @@ def test_DMP___init__():
     assert f.dom == ZZ
     assert f.lev == 1
 
+    raises(ValueError, lambda: DMP_Python([MPQ(2,1)], ZZ))
+    raises(ValueError, lambda: DMP_Python([2], QQ))
+
+
+def test_DMP_Python_convert():
+    assert not isinstance(DMP_Python([MPQ(2,1)], QQ).convert(ZZ).to_list()[0], MPQ)
+    assert isinstance(DMP_Python([2], ZZ).convert(QQ).to_list()[0], MPQ)
+
 
 def test_DMP_rep_deprecation():
     f = DMP([1, 2, 3], ZZ)