function: capture_payment()

		public function capture_payment( $order_id ) {
			$order = wc_get_order( $order_id );

			if ( 'stripe' === ( version_compare( WC_VERSION, '3.0.0', '<' ) ? $order->payment_method : $order->get_payment_method() ) ) {
				$charge   = get_post_meta( $order_id, '_stripe_charge_id', true );
				$captured = get_post_meta( $order_id, '_stripe_charge_captured', true );

				if ( $charge && 'no' === $captured ) {
					$result = WC_Stripe_API::request( array(
						'amount'   => $order->get_total() * 100,
						'expand[]' => 'balance_transaction',
					), 'charges/' . $charge . '/capture' );

					if ( is_wp_error( $result ) ) {
						$order->add_order_note( __( 'Unable to capture charge!', 'woocommerce-gateway-stripe' ) . ' ' . $result->get_error_message() );
					} else {
						$order->add_order_note( sprintf( __( 'Stripe charge complete (Charge ID: %s)', 'woocommerce-gateway-stripe' ), $result->id ) );
						update_post_meta( $order_id, '_stripe_charge_captured', 'yes' );

						// Store other data such as fees
						update_post_meta( $order_id, 'Stripe Payment ID', $result->id );
						update_post_meta( $order_id, '_transaction_id', $result->id );

						if ( isset( $result->balance_transaction ) && isset( $result->balance_transaction->fee ) ) {
							// Fees and Net needs to both come from Stripe to be accurate as the returned
							// values are in the local currency of the Stripe account, not from WC.
							$fee = ! empty( $result->balance_transaction->fee ) ? self::format_number( $result->balance_transaction, 'fee' ) : 0;
							$net = ! empty( $result->balance_transaction->net ) ? self::format_number( $result->balance_transaction, 'net' ) : 0;
							update_post_meta( $order_id, 'Stripe Fee', $fee );
							update_post_meta( $order_id, 'Net Revenue From Stripe', $net );
						}
					}
				}
			}
		}