Fix CS

Author: GromNaN

src/Query/Builder.php

@@ -49,7 +49,6 @@
 use function is_callable;
 use function is_float;
 use function is_int;
-use function is_null;
 use function is_string;
 use function md5;
 use function preg_match;
@@ -987,7 +986,7 @@ public function where($column, $operator = null, $value = null, $boolean = 'and'
             throw new ArgumentCountError(sprintf('Too few arguments to function %s(%s), 1 passed and at least 2 expected when the 1st is not an array or a callable', __METHOD__, var_export($column, true)));
         }
 
-        if (is_float($column) || is_bool($column) || is_null($column)) {
+        if (is_float($column) || is_bool($column) || $column === null) {
             throw new InvalidArgumentException(sprintf('First argument of %s must be a field path as "string". Got "%s"', __METHOD__, get_debug_type($column)));
         }