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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_notmuch_setting(self, section, key, fallback=None):
 """ look up config values from notmuch's config :param section: key is in :type section: str :param key: key to look up :type key: str :param fallback: fallback returned if key is not present :type fallback: str :returns: config value with type as specified in the spec-file """

        value = None
        if section in self._notmuchconfig:
            if key in self._notmuchconfig[section]:
                value = self._notmuchconfig[section][key]
        if value is None:
            value = fallback
        return value