bug :.validate() should return the validated data
solution:

def validate(self, attrs):
        attrs["mobile"] = attrs["username"]
        del attrs["code"]

        return attrs #漏填返回值

bug:圖片文件不顯示
solution:

#settings.py
STATIC_URL = '/static/'
MEDIA_URL = '/media/'
MEDIA_ROOT = os.path.join(BASE_DIR, 'media')

#urls.py
from django.views.static import serve
from django.urls import re_path
from Txshop.settings import MEDIA_ROOT

urlpatterns = [
    re_path(r'^media/(?P<path>.*)$', serve, {"document_root": MEDIA_ROOT}),
]