Executes the registered parsers to parse input configurations.

def parse(self):
        """
        Executes the registered parsers to parse input configurations.
        """

        self._config = _Config()

        self._setDefaults()

        for parser in self.parsers:
            for key, value in parser.parse(self, self._config).items():
                key = self._sanitizeName(key)
                if key not in self.configs:
                    raise UnknownConfigurationException(key)
                if value is not None:
                    self._setConfig(key, value)

        self._ensureRequired()
        self._cast()

        return self._config