Specify the commands that will accomplish the tasks specified below in the indicated order. Do not abbreviate commands.

$(1)$ Access the vlan $1$ switch virtual interface $($SVI$).(2)$ Set IP address $172\mathrm{.}16\mathrm{.}1\mathrm{.}1/26.(3)$ Activate the interface. $(4)$ Exit the interface to return to the mode immediately "above" the current mode.