How to remove dependent value from Dropdown?

Dash Python
1

Hi,

I have two Dropdowns:

    dcc.Dropdown(
        id='departments',
        options=[{'label': f"{dep}", 'value': f"{dep}"} for dep in sorted(df.department.unique())],
        value=['dep01'],
        multi=True
    ),

    dcc.Dropdown(
        id='employees',
        # options=[{'label': emp, 'value': emp} for emp in sorted(df.employee.unique())],
        # value=['P01'],
        multi=True
    ),

and a call back:

@app.callback(
    Output('employees', 'options'),
    Input('departments', 'value'),
    Input('include_dep_employees', 'value'))
def set_cities_options(departments, include_dep_employees):
    if include_dep_employees == ['Y']:
        emps = sorted(df.query("department.isin(@departments)").employee.unique())
    else:
        emps = sorted(df.employee.unique())
    return [{'label': emp, 'value': emp} for emp in emps]

If I select a department, I see only employees from selected department, but…
If I select two departments, and one employee from each department, and than remove one department, previously selected employee from removed department is still among values.

I would like to remove employee from employees dropdown if its department is removed.
How to do that?

Regards.