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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 set_value(self, key, value):
 # type: (str, Any) -> None """Modify a value in the configuration. """

        self._ensure_have_load_only()

        fname, parser = self._get_parser_to_modify()

        if parser is not None:
            section, name = _disassemble_key(key)

            # Modify the parser and the configuration
            if not parser.has_section(section):
                parser.add_section(section)
            parser.set(section, name, value)

        self._config[self.load_only][key] = value
        self._mark_as_modified(fname, parser)