error using DatePicker, I keep getting Not a valid date value even with the correct formatting. I need help, I can't figure out what is wrong - flask-wtforms

Question

I am working on a project and one of the modules are related to an appointment site using wtfform+DataField+flask
My form in appointment.html looks like this:
<form action="#" method="post" name="myform">
{{ form.csrf_token }}
{{ wtf.quick_form(form, novalidate=True, button_map={"submit": "primary"}) }}
my forms.py:
class DateForm(FlaskForm):
date = DateField("Date", format="'%Y-%m-%d'", validators=[Optional()])
hour = TimeField("Hour", format="'%H:%M'", validators=[Optional()])
submit = SubmitField("Submit")
My main.py
#app.route("/appointment", methods=["GET", "POST"])
def appointment():
form = DateForm()
if form.validate_on_submit():
session["date"] = form.date.data
session["hour"] = form.hour.data
return redirect(url_for('date'))
return render_template("appointment.html", form=form, current_user=current_user)
#app.route('/date', methods=['GET', 'POST'])
def date():
date = session["date"]
hour = session["hour"]
return render_template('date.html')
I have tested other alternatives but with the same result. No matter what, I'm still seeing the "Not a valid date value" and "Not a valid time value" messages.
I appreciate any help.
Thanks!!!
appointment

Answer 1

I've already solved this problem by adding InputRequired() as validator y the form, just like this:
date = DateField("Fecha", validators=([InputRequired(), DataRequired()]))
hour = TimeField("Hora", validators=([InputRequired(), DataRequired()]))