diff --git a/Pystan/config/sign_analysis.py b/Pystan/config/sign_analysis.py
index 38b4e9e2b1f6c8d4b1fd3f6f0ee7773c61b02f89..1d204b5ad331763d7981674774760bdcd08b2ef3 100644
--- a/Pystan/config/sign_analysis.py
+++ b/Pystan/config/sign_analysis.py
@@ -374,44 +374,51 @@ def reduce_state(s: state, c: BoolExpr) -> state:
 
 class Sign_interp(Transfer[state]):
     variables: frozenset[str]
-    def __init__(self,instr: Instr):
+
+    def __init__(self, instr: Instr):
         self.variables = variables_of_instr(instr)
+
     def bottom(self) -> state:
         return None
+
     def init_state(self) -> state:
         return dict.fromkeys(self.variables, sign.INT)
-    def join(self,s1:state,s2:state) -> state:
+
+    def join(self, s1: state, s2: state) -> state:
         if s1 is None: return s2
         if s2 is None: return s1
-        res: abstract_env = {}
-        for var in self.variables:
-            v1 = s1[var]
-            v2 = s2[var]
-            res[var] = sign_join(v1,v2)
-        return res
-
-    def included(self,s1: state,s2: state) -> bool:
+        return {v: sign_join(s1[v], s2[v]) for v in self.variables}
+
+    def included(self, s1: state, s2: state) -> bool:
         if s1 is None: return True
         if s2 is None: return False
-        for var in self.variables:
-            if not sign_leq(s1[var], s2[var]): return False
-        return True
+        return all(sign_leq(s1[v], s2[v]) for v in self.variables)
 
-    def tr_skip(self,s: state) -> state:
+    def tr_skip(self, s: state) -> state:
         return s
 
-    def tr_set(self,s: state,v: str,e: ArithExpr) -> state:
-        raise NotImplementedError
-
-    def tr_test(self,s: state,c: BoolExpr) -> state:
-        raise NotImplementedError
-
-    def tr_err(self,s: state,e: Expr) -> state:
-        if s is None: return s
-        if isinstance(e,ArithExpr):
-            raise NotImplementedError
-        if isinstance(e,BoolExpr):
-            raise NotImplementedError
+    def tr_set(self, s: state, v: str, e: ArithExpr) -> state:
+        if s is None: return None
+        val = eval_aexp(s, e)
+        if val is None or isinstance(val, Top):
+            s1 = s.copy()
+            s1[v] = sign.INT
+            return s1
+        s1 = s.copy()
+        s1[v] = val
+        return s1
+
+    def tr_test(self, s: state, c: BoolExpr) -> state:
+        return reduce_state(s, c)
+
+    def tr_err(self, s: state, e: Expr) -> state:
+        if s is None:
+            return s
+        match e:
+            case ArithExpr():
+                return s if eval_aexp(s, e) is not None else None
+            case BoolExpr():
+                return s if eval_bexp(s, e) is not None else None
 
 def analyze(i: Instr) -> None:
     cfg = Cfg(i)