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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 stringify(self, value):
 """Convert value to string This method is used to generate a simple JSON representation of the object (without dereferencing objects etc.) """

        # SuperModel -> UID
        if ISuperModel.providedBy(value):
            return str(value)
        # DateTime -> ISO8601 format
        elif isinstance(value, (DateTime)):
            return value.ISO8601()
        # Image/Files -> filename
        elif safe_hasattr(value, "filename"):
            return value.filename
        # Dict -> convert_value_to_string
        elif isinstance(value, dict):
            return {k: self.stringify(v) for k, v in value.iteritems()}
        # List -> convert_value_to_string
        if isinstance(value, (list, tuple, LazyMap)):
            return map(self.stringify, value)
        # Callables
        elif safe_callable(value):
            return self.stringify(value())
        elif isinstance(value, unicode):
            value = value.encode("utf8")
        try:
            return str(value)
        except (AttributeError, TypeError, ValueError):
            logger.warn("Could not convert {} to string".format(repr(value)))
            return None