What design pattern would I use to pass one user choice to all classes where inheritance doesn't seem appropriate?

I am building a Python application which calculates sales, stock available and parts required which first asks a user to choose their department from a combobox.

What design should I use to best inform all classes within the application of the choice of department? Once the department is chosen it remains used throughout the application and for the lifecycle of the application instance.

class Sales:

    def __init__(self, departmentname):
        self.departmentname = departmentname
        self.conn = pyodbc.connect(jsonhandler.get_json('connections.json'))


    def calculate_sales(self):
        with self.conn:
            departmentsalesvalues = pd.read_sql_query(f"""SELECT productcode, quantity, salesprice
                                      FROM salestable 
                                      WHERE department = ?""", self.conn, 
                                      params=(self.departmentname))
        return departmentsalesvalues

This works but it seems clumsy/a poor design. I believe I am missing a concept/pattern which would be useful in all programming languages. Can someone point me in the right direction please?

The questions I have asked myself: Should I create a Department class? But because the department is not similar to the other classes in any way inheritance seems to be out of the question. Should I pass this information around in a Main/App class? (Which is what i am currently doing.) Should I have an 'orchestrator' class which interfaces with the Main/App class?

I am quite new to building scalable applications but I find this sort of design question occurring more and more in my projects.