如何在django中定制UserCreationForm验证

from django import forms
from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth.models import User

class CustomUserCreationForm(UserCreationForm):
    # 添加自定义字段，例如电话号码
    phone_number = forms.CharField(max_length=15)

    class Meta:
        model = User
        fields = ['username', 'password1', 'password2', 'email', 'phone_number']

    def clean_phone_number(self):
        # 自定义电话号码验证规则
        phone_number = self.cleaned_data.get('phone_number')
        if not phone_number.isdigit():
            raise forms.ValidationError("电话号码只能包含数字")
        return phone_number

    def save(self, commit=True):
        user = super().save(commit=False)
        user.email = self.cleaned_data['email']
        user.phone_number = self.cleaned_data['phone_number']
        if commit:
            user.save()
        return user