How to filter objects that do not meet the conditions but without taking into account empty filters?

I have a function that should allow filtering the users to be uploaded to a list, the problem is that the filters (parameters) should be optional. I didn't find a way to ignore filters with value None. The following code is a situation similar to what I want to do, so you can run and test.

def get_participants(name=None, email=None, rol=None):
    # obtengo el listado
    trs = [
        {'name': 'ramon juanes', 'email': '[email protected]', 'rol': 'jefe'},
        {'name': 'lara galaz',   'email': '[email protected]', 'rol': 'trabajador'},
        {'name': 'samuel adobe', 'email': '[email protected]', 'rol': 'trabajador'},
        {'name': 'juan carlos',  'email': '[email protected]', 'rol': 'supervisor'},
    ]
    participants = []
    for tr in trs:
        user = Participant(tr)
        # momento del filtro
        # si un filtro es None produce un TypeError
        # if name in user.name and email in user.name and rol in user.rol:
        #     participants.append(user)

        # si un filtro es None no toma en cuenta al resto de los campos
        # if (name and name in user.name) and (email and email in user.name) and (rol and rol in user.rol):
        #    participants.append(user)

        # este caso no tiene sentido tomarlo debido al siguiente resultado:
        # len(get_participants(name='lara', email='minum')) -> 2, pero debería ser 0, ya que no esta en listado
        # if (name and name in user.name) or (email and email in user.name) or (rol and rol in user.rol):
        #   participants.append(user)
    return participants

class Participant:
    def __init__(self, tr):
        self.name = tr['name']
        self.email = tr['email']
        self.rol = tr['rol']

In the original code:

def get_participants(self, subject_id, name=None, email=None, rol=None):
    self.open_with_session(f'https://www.page.com/user/index.php?id={subject_id}')
    trs = self.page.select('#participants tbody tr')
    participants = []
    for tr in trs:
        user = Participant(tr)
        # TypeError cuando name, email o rol es None
        if name in user.name and email in user.name and rol in user.rol:
            participants.append(user)
    return participants

class Participant:
    def __init__(self, tr):
        self.name = tr.select_one('.c1').text.lower()
        self.email = tr.select_one('.c2').text.lower()
        self.rol = tr.select_one('.c3').text.strip().lower()

I've tried using the argument **kwargsbut that would mean turning my objects Participantinto dictionaries, and using a forwith a break, which takes some of the elegance out of the code:

def get_participants(**kwargs):
    # obtengo el listado
    trs = [
        {'name': 'ramon juanes', 'email': '[email protected]', 'rol': 'jefe'},
        {'name': 'lara galaz',   'email': '[email protected]', 'rol': 'trabajador'},
        {'name': 'samuel adobe', 'email': '[email protected]', 'rol': 'trabajador'},
        {'name': 'juan carlos',  'email': '[email protected]', 'rol': 'supervisor'},
    ]
    participants = []
    for tr in trs:
        user = {
            'name': tr['name'], # tr.select_one('.c1').text.lower()
            'email': tr['email'], # tr.select_one('.c2').text.lower()
            'rol': tr['rol'], # tr.select_one('.c3').text.strip().lower()
        }
        append = True
        for key in kwargs.keys():
            if not kwargs[key] in user[key]:
                append = False
                break
        if append:
           participants.append(user)
    return participants

This code works, but I would like to know if there is a simpler way to accomplish this task and without having to use dictionaries (replacing my objects Participant).

From already thank you very much.