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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 _trim_value(self, value):
 """Trim double quotes off the ends of a value, un-escaping inner double quotes and literal backslashes. Also convert escapes to unicode. If the string is not quoted, return it unmodified. """


        if value[0] == '"':
            assert value[-1] == '"'
            value = value[1:-1].replace('\\"', '"').replace("\\\\", "\\")
            return Parser._unescape_re.sub(Parser._unescape_fn, value)
        return value