WP recursive arg merging

yag.php

<?php

		$args = array(
				'meta_query' => array(
						'relation' => 'AND',
						array(
								'key'   => 'meta_key_one',
								'value' => '1'
						)
				)
		);
		
		$extra_args = array(
				'meta_query' => array(
					array(
							'key'   => 'meta_key_two',
							'value' => '1'
					)
				)
			) );

		$args = wp_parse_args( $args, $extra_args );
		/**
		OUTPUT:
		array (size=1)
  'meta_query' => 
    array (size=1)
      0 => 
        array (size=2)
          'key' => string 'meta_key_two' (length=12)
          'value' => string '1' (length=1)
  **/
  
  $args = array_merge_recursive( $args, $extra_args );
  /**
  OUTPUT:
  array (size=1)
  'meta_query' => 
    array (size=3)
      'relation' => string 'AND' (length=3)
      0 => 
        array (size=2)
          'key' => string 'meta_key_one' (length=12)
          'value' => string '1' (length=1)
      1 => 
        array (size=2)
          'key' => string 'meta_key_two' (length=12)
          'value' => string '1' (length=1)
  **/