null is not an object

[ZahraShams]

installed library with react-native 61.2 , and userd sample
but gets error

below is the code

import * as React from 'react';
import { View, TouchableOpacity, Image, Text, StyleSheet } from 'react-native';
import { Calendar, CalendarList, Agenda } from 'react-native-general-calendars';

class App extends React.Component {
constructor() {
super()

}

render() {
return (



);
}
}
export default App;
const styles = StyleSheet.create({
container: {
flex: 1,
marginTop: 40,
},
});