Jinja2/Flask, I Can't get a dynamic value from a checkbox

So i have this html

<label class="continer">Empresa Confidencial
     
     <input type="checkbox" id="confidencial" name="confidencial" value="0">
     
     <span class="checkmark"></span>
</label>

proyect.py

def editar_(confidencial,estado,id):
    cur = mysql.connection.cursor()
    cur.execute('UPDATE proyecto set EMPRESA_CONFIDENCIAL=%s,estado=%s where PK_PROYECTO=%s', (confidencial,estado, id,))
    mysql.connection.commit()

adminviews.py

@app.route("/editar", methods=["POST"])
def editar():
    print('.................................................................................')
    id = request.form['id']
    estado = request.form.get('estado') 
    confidencial = request.form.get('confidencial')
    print(id,str(estado), str(confidencial))
    pr.editar_(confidencial,estado,id)
    return redirect(url_for('empresasT'))

And i need to get the value "1" or "0" to send it to the database, the problem is that when i run the code, without the "confidencial" in proyect.py and adminvie.py, it runs and make changes in the database, but when i try again with the "confidencial", and make a change in the checkbox, if the checkbox is checked and i unchecked it the value is none, but if i leave it checked, the value is the one by default, the console it says that the value is null, MySQLdb._exceptions.OperationalError: (1048, "Column 'EMPRESA_CONFIDENCIAL' cannot be null"), the process is not getting the value "1" or "0" from the checkbox after the modification, but the other values that i got like id and estado does, i think is the if statement, how can i get the value from the checkbox in the html using the if statement