Explicitly delete the PySymbol

Author: isuruf

symengine/lib/symengine_wrapper.pyx

@@ -538,6 +538,9 @@ cdef class Basic(object):
     def __dealloc__(self):
         self.thisptr.reset()
 
+    def _unsafe_reset(self):
+        self.thisptr.reset()
+
     def __add__(a, b):
         cdef Basic A = _sympify(a, False)
         B_ = _sympify(b, False)
@@ -2717,6 +2720,7 @@ false = c2py(symengine.boolFalse)
 
 def module_cleanup():
     global I, E, pi, oo, zoo, nan, true, false, sympy_module, sage_module
+    funcs.clear()
     del I, E, pi, oo, zoo, nan, true, false, sympy_module, sage_module
 
 import atexit

symengine/tests/test_sympy_compat.py

@@ -192,7 +192,8 @@ def __init__(self, name, extra_attribute):
     two_x = 2 * x
     # Check that after arithmetic, same subclass is returned
     assert two_x.args[1] is x
-
+    del two_x
+    x._unsafe_reset()
 
 def test_Abs():
     x = symbols("x")