# the current implementation also changes the username, i.e. it would need an additional parameter, I can't support it and I would forbid it anyway.
changeAttributes(ident username, string firstName, string lastName, string email, string password) {
  assume exists //accounts/account[username]; # implicitly true in OO implementations
 
  update //accounts/account[username]/firstName firstName;
  update //accounts/account[username]/lastName lastName;
  update //accounts/account[username]/email email;
  update //accounts/account[username]/password password;
}