Which compound is formed when excess KCN is added to aqueous solution of copper sulphate?

${\mathrm{K}}_3\left[\mathrm{Cu}(\mathrm{CN}{)}_4\right]$ formed when excess KCN is added to an aqueous solution of copper sulphate

When an excess of KCN is added to an aqueous solution of ${\mathrm{CuSO}}_4$ following reaction is observe,

  $\mathrm{CuCN}+3\mathrm{Ka}\to {\mathrm{K}}_3\left[\mathrm{Cu}(\mathrm{CN}{)}_4\right]$