How would you determine the standard electrode potential of the system `Mg^(2+)|Mg`?

Explanation

An electrode is set up with a Mg wire dipped into a 1M wire dipped into a 1 M solution of `Mg^(2+)` ions. This electrode is connected to a standard hydrogen electrode (SHE), `Pt, H_(2)"(1 atm)"H^(+)|(1M)`, and thus a cell is set up. It is represented as :
`Mh|Mg^(2+)(1M)||H^(+)(1M)|H_(2)"(1 atm)"Pt`
`therefore" "E_("cell")^(@)=E_("Right")^(@)-E_("Left")^(@)=E_(H^(+)|(1)/(2)H_(2))^(@)E_(Mg^(2+)|Mg)^(@)`
`=0-E_(Mg^(2+)|Mg)^(@)`
`therefore" "E_(Mg^(2+)|Mg)^(@)=-E_("cell")^(@)`