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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def build_standard_field(self, field_name, model_field):
 """ Create regular model fields. """

        field_mapping = ClassLookupDict(self.serializer_field_mapping)

        field_class = field_mapping[model_field]
        field_kwargs = get_field_kwargs(field_name, model_field)

        if 'choices' in field_kwargs:
            # Fields with choices get coerced into `ChoiceField`
            # instead of using their regular typed field.
            field_class = self.serializer_choice_field
            # Some model fields may introduce kwargs that would not be valid
            # for the choice field. We need to strip these out.
            # Eg. models.DecimalField(max_digits=3, decimal_places=1, choices=DECIMAL_CHOICES)
            valid_kwargs = set((
                'read_only', 'write_only',
                'required', 'default', 'initial', 'source',
                'label', 'help_text', 'style',
                'error_messages', 'validators', 'allow_null', 'allow_blank',
                'choices'
            ))
            for key in list(field_kwargs.keys()):
                if key not in valid_kwargs:
                    field_kwargs.pop(key)

        if not issubclass(field_class, ModelField):
            # `model_field` is only valid for the fallback case of
            # `ModelField`, which is used when no other typed field
            # matched to the model field.
            field_kwargs.pop('model_field', None)

        if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField):
            # `allow_blank` is only valid for textual fields.
            field_kwargs.pop('allow_blank', None)

        if postgres_fields and isinstance(model_field, postgres_fields.ArrayField):
            # Populate the `child` argument on `ListField` instances generated
            # for the PostgrSQL specfic `ArrayField`.
            child_model_field = model_field.base_field
            child_field_class, child_field_kwargs = self.build_standard_field(
                'child', child_model_field
            )
            field_kwargs['child'] = child_field_class(**child_field_kwargs)

        return field_class, field_kwargs