diff --git a/src/api/api_ast.cpp b/src/api/api_ast.cpp
index a8f4d74b7..bc76d02bc 100644
--- a/src/api/api_ast.cpp
+++ b/src/api/api_ast.cpp
@@ -660,11 +660,14 @@ extern "C" {
         LOG_Z3_get_domain(c, d, i);
         RESET_ERROR_CODE();
         CHECK_VALID_AST(d, nullptr);
-        if (i >= to_func_decl(d)->get_arity()) {
+        func_decl* _d = to_func_decl(d);
+        if (_d->is_associative()) 
+            i = 0;
+        if (i >= _d->get_arity()) {
             SET_ERROR_CODE(Z3_IOB, nullptr);
             RETURN_Z3(nullptr);
         }
-        Z3_sort r = of_sort(to_func_decl(d)->get_domain(i));
+        Z3_sort r = of_sort(_d->get_domain(i));
         RETURN_Z3(r);
         Z3_CATCH_RETURN(nullptr);
     }
diff --git a/src/api/python/z3/z3.py b/src/api/python/z3/z3.py
index 074570b03..cf5be3e07 100644
--- a/src/api/python/z3/z3.py
+++ b/src/api/python/z3/z3.py
@@ -763,8 +763,6 @@ class FuncDeclRef(AstRef):
         >>> f.domain(1)
         Real
         """
-        if z3_debug():
-            _z3_assert(i < self.arity(), "Index out of bounds")
         return _to_sort_ref(Z3_get_domain(self.ctx_ref(), self.ast, i), self.ctx)
 
     def range(self):
@@ -834,8 +832,6 @@ class FuncDeclRef(AstRef):
         """
         args = _get_args(args)
         num = len(args)
-        if z3_debug():
-            _z3_assert(num == self.arity(), "Incorrect number of arguments to %s" % self)
         _args = (Ast * num)()
         saved = []
         for i in range(num):