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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 _accept_header(self):
 """ Method for determining correct `Accept` header. Different resources and different GoCD version servers prefer a diverse headers. In order to manage all of them, this method tries to help: if `VERSION_TO_ACCEPT_HEADER` is not provided, if would simply return default `ACCEPT_HEADER`. Though if some manager specifies `VERSION_TO_ACCEPT_HEADER` class variable, then it should be a dictionary: keys should be a versions and values should be desired accept headers. Choosing is pessimistic: if version of a server is less or equal to one of the dictionary, the value of that key would be used. :return: accept header to use in request. """

        if not self.VERSION_TO_ACCEPT_HEADER:
            return self.ACCEPT_HEADER

        return YagocdUtil.choose_option(
            version_to_options=self.VERSION_TO_ACCEPT_HEADER,
            default=self.ACCEPT_HEADER,
            server_version=self._session.server_version
        )