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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 _homedir_setter(self, directory):
 """Set the directory to use as GnuPG's homedir. If unspecified, use $HOME/.config/python-gnupg. If specified, ensure that the ``directory`` does not contain various shell escape characters. If ``directory`` is not found, it will be automatically created. Lastly, the ``direcory`` will be checked that the EUID has read and write permissions for it. :param str directory: A relative or absolute path to the directory to use for storing/accessing GnuPG's files, including keyrings and the trustdb. :raises: :exc:`~exceptions.RuntimeError` if unable to find a suitable directory to use. """

        if not directory:
            log.debug("GPGBase._homedir_setter(): Using default homedir: '%s'"
                      % _util._conf)
            directory = _util._conf

        hd = _parsers._fix_unsafe(directory)
        log.debug("GPGBase._homedir_setter(): got directory '%s'" % hd)

        if hd:
            log.debug("GPGBase._homedir_setter(): Check existence of '%s'" % hd)
            _util._create_if_necessary(hd)

        if self.ignore_homedir_permissions:
            self._homedir = hd
        else:
            try:
                log.debug("GPGBase._homedir_setter(): checking permissions")
                assert _util._has_readwrite(hd), \
                    "Homedir '%s' needs read/write permissions" % hd
            except AssertionError as ae:
                msg = ("Unable to set '%s' as GnuPG homedir" % directory)
                log.debug("GPGBase.homedir.setter(): %s" % msg)
                log.debug(str(ae))
                raise RuntimeError(str(ae))
            else:
                log.info("Setting homedir to '%s'" % hd)
                self._homedir = hd