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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 full_symbol(self):
 """Returns the symbol under the cursor AND additional contextual symbols in the case of %-separated lists of type members."""

        if self._full_symbol is None:
            self._full_symbol = self._symbol_extract(cache.RE_FULL_CURSOR, brackets=True)

        return self._full_symbol