remove (again) sympy_dummy attribute from symbols

Author: mmatera

mathics/core/symbols.py

@@ -342,7 +342,6 @@ class Symbol(Atom, NumericOperators, EvalMixin):
 
     name: str
     hash: int
-    sympy_dummy: Any
     _short_name: str
 
     # Dictionary of Symbols defined so far.
@@ -355,7 +354,7 @@ class Symbol(Atom, NumericOperators, EvalMixin):
 
     # __new__ instead of __init__ is used here because we want
     # to return the same object for a given "name" value.
-    def __new__(cls, name: str, sympy_dummy=None):
+    def __new__(cls, name: str):
         """
         Allocate an object ensuring that for a given ``name`` and ``cls`` we get back the same object,
         id(object) is the same and its object.__hash__() is the same.
@@ -383,20 +382,7 @@ def __new__(cls, name: str, sympy_dummy=None):
             # Python objects, so we include the class in the
             # event that different objects have the same Python value.
             # For example, this can happen with String constants.
-
             self.hash = hash((cls, name))
-
-            # TODO: revise how we convert sympy.Dummy
-            # symbols.
-            #
-            # In some cases, SymPy returns a sympy.Dummy
-            # object. It is converted to Mathics as a
-            # Symbol. However, we probably should have
-            # a different class for this kind of symbols.
-            # Also, sympy_dummy should be stored as the
-            # value attribute.
-            self.sympy_dummy = sympy_dummy
-
             self._short_name = strip_context(name)
 
         return self
@@ -405,7 +391,7 @@ def __eq__(self, other) -> bool:
         return self is other
 
     def __getnewargs__(self):
-        return (self.name, self.sympy_dummy)
+        return (self.name,)
 
     def __hash__(self) -> int:
         """
@@ -703,6 +689,9 @@ def __new__(cls, name, value):
             self.hash = hash((cls, name))
         return self
 
+    def __getnewargs__(self):
+        return (self.name, self._value)
+
     @property
     def is_literal(self) -> bool:
         """