WordPress Post Date Query for this month's posts and previous month's posts

post_query.php

<?php
global $current_user;
$ThisMonthArgs = array(
    'post_type' => 'post',
    'author'=> $current_user->ID,
    'posts_per_page' => -1,
    'date_query' => array(
        array(
            'column' => 'post_modified_gmt',
            'after' => array(
                'year'  => date('Y'),
                'month' => date('m'),
                'day'   => 01,
            ),
        ),
        array(
            'column' => 'post_modified_gmt',
            'before'  => array(
                'year'  => date('Y'),
                'month' => date('m'),
                'day'   => date('t'),
            ),
        ),
    ),
);

$LastMonthArgs = array(
    'post_type' => 'post',
    'author'=> $current_user->ID,
    'posts_per_page' => -1,
    'date_query' => array(
        array(
            'column' => 'post_modified_gmt',
            'before' => array(
                'year'  => date('Y', strtotime('-1 Month')),
                'month' => date('m', strtotime('-1 Month')),
                'day'   => date('t', strtotime('-1 Month')),
            ),
        ),
        array(
            'column' => 'post_modified_gmt',
            'after'  => array(
                'year'  => date('Y', strtotime('-1 Month')),
                'month' => date('m', strtotime('-1 Month')),
                'day'   => 01
            ),
        )
    ),
);
?>