Update app.py

app.py

@@ -17,13 +17,13 @@ def calculator(x: float, y: float, operation: str)-> str:
         operation: one of ["+", "-", "*", "/"].
     """
     if operation == "+":
-        return str(f"{x}+{y} = {x+y}")
+        return str(f"{x} + {y} = {x+y}")
     elif operation == "-":
-        return str(f"{x}-{y} = {x-y}")
+        return str(f"{x} - {y} = {x-y}")
     elif operation == "*":
-        return str(f"{x}*{y} = {x*y}")
+        return str(f"{x} * {y} = {x*y}")
     elif operation == "/":
-        return str(f"{x}/{y} = {x/y}")
+        return str(f"{x} / {y} = {x/y}")
     else:
         raise ValueError("operation must be one of ['+', '-', '*', '/']")