PHP parse error: syntax error, unexpected ‘use’

After a long search, I finally found the reason, not the PHP version [], that I wrote use in the methods of the class.
This thing cannot be used independently of the class, otherwise it would be considered a namespace.
The test example is as follows

// Trait.php

trait CustomerFunctionsTrait {

    public function plus ( $a = 1, $b = 1 ) { 
        echo $a + $b; 
    }   

    public function minus ( $a = 5, $b = 1 ) { 
        echo $a - $b; 
    }   

}


// Test.php
include './Trait.php';
class MyTest {
    use CustomerFunctionsTrait;
    public function plus () {
        // use CustomerFunctionsTrait;  //This is where I made a mistake, writing use into the method body -!!!!
        echo 'str';
    }
}

$n = new MyTest;
$n->minus();


Read More: