TypeError: a is not a function.

My React-Native app was working fine until I suddenly got this strange error. I did not add an ‘a’ function nor am passing “a” function anywhere in my code.

App.js

import React from "react";
import { Platform, StatusBar, StyleSheet, View } from "react-native";
import { Provider } from "react-redux";
import { createStore, applyMiddleware, compose } from "redux";
import { persistStore } from "redux-persist";
import redux-thunk from "redux-thunk";
import reducers from "redux/reducers";
import Screens from "screens";


// Configure REACT, REDUX DEVTOOLS for debugging
const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;
const store = createStore(
  reducers,
  composeEnhancers(applyMiddleware(reduxThunk))
);

const persistor = persistStore(store);

export default class App extends React.PureComponent {

    render(){
      return (
        <Provider store={store}>
          <View style={styles.container}>
            {Platform.OS === "ios" && <StatusBar barStyle="default" />}
            <Screens />
          </View>
        </Provider>
      );
     }

    }
  }