Budgets.cs

Budget {
  public double CalculateTotal() { ... }
}

/* ---- */
OneClient {
  ...
    budget.CalculateTotal();
  ...
}
/* ---- */
OtherClient {
    ...
    budget.CalculateTotal();
    ...
}



/* new changes => Take into account spanish taxes */

OneClient {
  ...
    budget.CalculateTotal(0);
  ...
}
/* ---- */
OtherClient {
    ...
    budget.CalculateTotal(0);
    ...
}
/* ---- */
Budget {
  public double CalculateTotal(int taxAmount) { ... }
}





/* remove duplicated code */
OneClient {
  ...
    budget.CalculateTotal(spainTaxes.Get());
  ...
}
/* ---- */
OtherClient {
    ...
    budget.CalculateTotal(spainTaxes.Get());
    ...
}
/* ---- */
Budget {
  public double CalculateTotal(int taxAmount) { ... }
}

SpainTaxes {
  public int Get() {
    return 0;
  }
}




/* new changes => last step when finish to add code in Budget */

SpainTaxes {
  public int Get() {
    return 21;
  }
}