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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 add_default(self, model, name, default):
 """Add default."""

        field = model._meta.fields[name]
        model._meta.defaults[field] = field.default = default
        self.ops.append(self.migrator.apply_default(model._meta.table_name, name, field))
        return model