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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_prep_value(self, value):
 		""" Return the integer value to be stored from the hex string """

		if value is None or value == "":
			return None
		if isinstance(value, six.string_types):
			value = _hex_string_to_unsigned_integer(value)
		if _using_signed_storage():
			value = _unsigned_to_signed_integer(value)
		return value