complete

utils.py

@@ -4,41 +4,63 @@
 complete methods below and add missing methods according to the tests.
 
 """
-class Calculator():
-    """rounding_digits is a default value by which 
+
+
+class Calculator:
+    """rounding_digits is a default value by which
     the calculator rounds off numbers 10/3 = 3.3333333333...
-    if rounding_digits = 2 the answer for this expression is 3.33  
+    if rounding_digits = 2 the answer for this expression is 3.33
     """
+
     rounding_digits = 0
-    
-    def __init__(self,round_digits):
+
+    def __init__(self, round_digits):
         self.rounding_digits = round_digits
-
-    def addtion(self,a,b):
-        return 0
-    def subtraction(self,a,b):
-        return 0
-    def multiplication(self,a,b):
-        return 0
-    def division(self,a,b):
-        return 0
-
+
+    def addtion(self, a, b):
+        return self._round(a + b, self.rounding_digits)
+
+    def subtraction(self, a, b):
+        return self._round(a - b, self.rounding_digits)
+
+    def multiplication(self, a, b):
+        return self._round(a * b, self.rounding_digits)
+
+    def division(self, a, b):
+        return self._round(a / b, self.rounding_digits)
+
     @property
     def round_digits(self):
         return self.rounding_digits
-    
-    def set_ound_digits(self,digits):
+
+    def set_round_digits(self, digits):
         self.rounding_digits = digits
-
-
-class History():
-    filepath_ = ""
+
+    @staticmethod
+    def _round(answer: float, decimal: int | None = None) -> float:
+        if decimal is not None and isinstance(decimal, int) and decimal > 0:
+            return round(answer, decimal)
+        return answer
+
+
+class History:
+    def __init__(self, filepath="History.txt"):
+        self.filepath_ = filepath
+
     def __init__(self, filepath):
         self.filepath_ = filepath
-
-    def save(self,expression:str):
-        pass
-    def restore(self)->list[str]:
-        pass
+
+    def save(self, expression: str):
+        with open(self.filepath_, "a", encoding="utf-8", errors="ignore") as file:
+            file.write(expression + "\n")
+
+    def restore(self) -> list[str]:
+        try:
+            with open(self.filepath_, "r", encoding="utf-8", errors="ignore") as file:
+                return [line.strip() for line in file if line.strip()]
+        except FileNotFoundError:
+            return []
+
     def clear(self):
-        pass
+        with open(self.filepath_, "w", encoding="utf-8", errors="ignore"):
+            pass