Activate WebDevStudio's cmb class

gistfile1.phtml

<?php 
/**
 * Initialize Custom Metabox class.
 * https://github.com/WebDevStudios/Custom-Metaboxes-and-Fields-for-WordPress
 * https://github.com/mustardBees/cmb_field_map
 */
function sendtheme_initialize_metaboxes() {
        
        if ( !class_exists( 'cmb_Meta_Box' ) ) {
	      require_once get_template_directory() . '/metaboxes-1.2.0/init.php';
        }
        
}
add_action( 'init', 'sendtheme_initialize_metaboxes', 9999 );





/**
 * Add Custom Metaboxes.
 */
function sendtheme_create_metaboxes( $metaboxes ) {  

        $metaboxes[0] = array(
                'id'         => 'geotagging_details',
                'title'      => __( 'Location details', 'mytheme' ),
                'pages'      => array( 'post' ),
                'context'    => 'normal',
                'priority'   => 'default',
                'show_names' => true,
                'fields'     => array(            
		    array(
			  'name' => __( 'Location', 'mytheme' ),
			  'id'   => 'geo',
			  'type' => 'pw_map',
			  'sanitization_cb' => 'pw_map_sanitise',	
		    ),
                        array(
                                'name' => __( 'Public?', 'mytheme' ),
                                'id'   => 'geo_public',
                                'type' => 'select',
                                'options' => array(
                                        array( 'name' => __( 'No', 'mytheme' ), 'value' => 'false', ),		    
                                        array( 'name' => __( 'Yes', 'mytheme' ), 'value' => 'true', ),		    
                                ),		
                        ),		    
                ),
        );
        
        return $metaboxes;
    
}
add_filter( 'cmb_meta_boxes' , 'sendtheme_create_metaboxes' );