ORA-01036: illegal variable name/number, binding

Question

I am currently trying to bind variables into a SQL Query. I am using the Cx_Oracle Library.

c.execute("""
    select employee_id, first_name, last_name, TO_CHAR(hire_date, 'mm/dd/yyyy'), salary from employees
    order by 1
    """)

This Query work perfectly fine and I get the desired output.

But if I try these two queries, I get the cx_Oracle.DatabaseError: ORA-01036: illegal variable name/number

I tried these methods to bind the variables:

tempo = "employees"
test_query = "select employee_id, first_name, last_name, TO_CHAR(hire_date, 'mm/dd/yyyy'), salary from :temp"
    c.execute(test_query, temp=tempo)

--> Error I mentioned earlier

The second method:

c.execute("""
    select employee_id, first_name, last_name, TO_CHAR(hire_date, 'mm/dd/yyyy'), salary from :table_name
    order by 1
    """, table_name="employees")

--> cx_Oracle.DatabaseError: ORA-00903: Invalid Table Name

I don't understand, why this binding isn't working, does anyone have a clue? Thanks in advance