Update handler.py

You are loading a {"inputs": {{"customerID": {"0": "7590-VHVEG", "1": "5575-GNVDE", ...}} as dataframe -> which ends up as 1 column thats why you receive the `KeyError`.

handler.py

@@ -22,7 +22,7 @@ class EndpointHandler():
         """
         inputs = data.pop("inputs", data)
         parameters = data.pop("parameters", None)
-        df = pd.DataFrame(data)
+        df = pd.DataFrame(inputs)
 
         df["TotalCharges"] = df["TotalCharges"].replace(" ", np.nan, regex=False).astype(float)
         df = df.drop(columns=["customerID"])