src/Model/Admin.php
public function unsetAdminData($key, $userId = null)
    {
        return $this->setUnsetAdminData($key, null, $userId, false);
    }
public function unsetAdminData($key, $userId = null)
    {
        return $this->setUnsetAdminData($key, null, $userId, false);
    }
Unsets a piece of admin data

@param  string $key    The key to set
@param  mixed  $userId The user's ID, if null active user is used.

@return boolean