add sources meta “tag”

class Custom_Sources_Meta {

	public function __construct() {

		if ( is_admin() ) {

			add_action( 'sources_add_form_fields',  array( $this, 'create_screen_fields'), 10, 1 );
			add_action( 'sources_edit_form_fields', array( $this, 'edit_screen_fields' ),  10, 2 );

			add_action( 'created_sources', array( $this, 'save_data' ), 10, 1 );
			add_action( 'edited_sources',  array( $this, 'save_data' ), 10, 1 );

		}

	}

	public function create_screen_fields( $taxonomy ) {

		// Set default values.
		$sources_taxtag = '';

		// Form fields.
		echo '<div class="form-field term-sources_taxtag-wrap">';
		echo '	<label for="sources_taxtag">' . __( 'taxtag', 'text_domain' ) . '</label>';
		echo '	<input type="text" id="sources_taxtag" name="sources_taxtag" placeholder="' . esc_attr__( '', 'text_domain' ) . '" value="' . esc_attr( $sources_taxtag ) . '">';
		echo '</div>';

	}

	public function edit_screen_fields( $term, $taxonomy ) {

		// Retrieve an existing value from the database.
		$sources_taxtag = get_term_meta( $term->term_id, 'sources_taxtag', true );

		// Set default values.
		if( empty( $sources_taxtag ) ) $sources_taxtag = '';

		// Form fields.
		echo '<tr class="form-field term-sources_taxtag-wrap">';
		echo '<th scope="row">';
		echo '	<label for="sources_taxtag">' . __( 'taxtag', 'text_domain' ) . '</label>';
		echo '</th>';
		echo '<td>';
		echo '	<input type="text" id="sources_taxtag" name="sources_taxtag" placeholder="' . esc_attr__( '', 'text_domain' ) . '" value="' . esc_attr( $sources_taxtag ) . '">';
		echo '</td>';
		echo '</tr>';

	}

	public function save_data( $term_id ) {

		// Sanitize user input.
		$sources_new_taxtag = isset( $_POST[ 'sources_taxtag' ] ) ? sanitize_text_field( $_POST[ 'sources_taxtag' ] ) : '';

		// Update the meta field in the database.
		update_term_meta( $term_id, 'sources_taxtag', $sources_new_taxtag );

	}

}

new Custom_Sources_Meta;