Why DjangoRF serializer is_valid is false?

Question

My class

class SprintSerializer(serializers.ModelSerializer):

    links = serializers.SerializerMethodField()

    class Meta:
        model = Sprint
        fields = ('id', 'name', 'description', 'end', 'links', )

In my shell,I populated a serializer with data

serializer = SprintSerializer(data=({'name':'JHolmes','description':'ambassador','end':'2019-01-27T15:17:10.375877'}))

Then

serializer.data
{'name': 'JHolmes', 'description': 'ambassador', 'end': '2019-01-27T15:17:10.375877'}
serializer.validated_data
{}
serializer.is_valid()
False

Why is an instance serializer False? EDIT As Berry pointed out,data format was wrong

serializer.errors
{'end': [ErrorDetail(string='Date has wrong format. Use one of these formats instead: YYYY[-MM[-DD]].', code='invalid')]}

Solved issue

'end':'2019-01-27'
serializer.is_valid()
True

Answer 1

Just use below code to find out validation errors:

print(serializer.errors)