text: import React from 'react'
  import { View, Text, Button } from 'react-native'
  
  
  
  
  
  const SignIn = ({ navigation }) => {
  
      function SignIn() {
          return (
              <View>
                  <Text>SignIn</Text>
                  <Button 
                      title="Cliente"
                      onPress={() => navigation.navigate('Cliente')}
                  />
  
                  <Button 
                      title="Vendedor"
                      onPress={() => navigation.navigate('Vendedor')}
                  />
  
                  <Button 
                      title="Administrador"
                      onPress={() => navigation.navigate('Administrador')}
                  />
              </View>
          );
      }
  
      
  
  
      return (
          <View>
              <SignIn />
          </View>
      )
  }
  
  export default SignIn
  