fix example

datafusion/functions/src/utils.rs

@@ -30,6 +30,7 @@ use datafusion_expr::ColumnarValue;
 /// # use datafusion_common::ScalarValue;
 /// # use datafusion_common::Result;
 /// # use datafusion_expr_common::columnar_value::ColumnarValue;
+/// # use datafusion_functions::utils::take_function_args;
 /// fn my_function(args: &[ColumnarValue]) -> Result<()> {
 ///   // function expects 2 args, so create a 2-element array
 ///   let [arg1, arg2] = take_function_args("my_function", args)?;
@@ -41,7 +42,7 @@ use datafusion_expr::ColumnarValue;
 /// let ten = ColumnarValue::from(ScalarValue::from(10i32));
 /// let twenty = ColumnarValue::from(ScalarValue::from(20i32));
 /// let args = vec![ten.clone()];
-///  let err = my_function(&args).unwrap_err();
+/// let err = my_function(&args).unwrap_err();
 /// assert_eq!(err.to_string(), "my_function function requires 2 arguments, got 1");
 /// // Calling the function with 2 arguments works great
 /// let args = vec![ten, twenty];