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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 _get_upload_arguments(self, content_type):
 """Get required arguments for performing an upload. The content type returned will be determined in order of precedence: - The value passed in to this method (if not :data:`None`) - The value stored on the current blob - The default value ('application/octet-stream') :type content_type: str :param content_type: Type of content being uploaded (or :data:`None`). :rtype: tuple :returns: A triple of * A header dictionary * An object metadata dictionary * The ``content_type`` as a string (according to precedence) """

        headers = _get_encryption_headers(self._encryption_key)
        object_metadata = self._get_writable_metadata()
        content_type = self._get_content_type(content_type)
        return headers, object_metadata, content_type