Email Validator

class EmailValidator:
    def __init__(self, min_length: int, mails: list, domains: list):
        self.min_length = min_length
        self.mails = mails
        self.domains = domains

    def __validate_name(self, name):
        return len(name) >= self.min_length

    def __validate_mail(self, mail):
        return mail in self.mails

    def __validate_domain(self, domain):
        return domain in self.domains

    def validate(self, email: str):
        if email and '@' in email:
            symbol = email.index('@')
            name = email[:symbol]
            dot_idx = email.index('.')
            mail = email[symbol + 1:dot_idx]
            domain = email[dot_idx + 1:]
            if EmailValidator.__validate_name(self, name) and EmailValidator.__validate_mail(self, mail) and EmailValidator.__validate_domain(self, domain):
                return True
            return False