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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 fieldstorage(self):
 """ `cgi.FieldStorage` from `wsgi.input`. """

        if self._fieldstorage is None:
            if self._body is not None:
                raise ReadBodyTwiceError()

            self._fieldstorage = cgi.FieldStorage(
                environ=self._environ,
                fp=self._environ['wsgi.input']
            )

        return self._fieldstorage