def get_project_properties(self, project_id, keys=None):
        """GetProjectProperties.
        [Preview API] Get a collection of team project properties.
        :param str project_id: The team project ID.
        :param [str] keys: A comma-delimited string of team project property names. Wildcard characters ("?" and "*") are supported. If no key is specified, all properties will be returned.
        :rtype: [ProjectProperty]
        """
        route_values = {}
        if project_id is not None:
            route_values['projectId'] = self._serialize.url('project_id', project_id, 'str')
        query_parameters = {}
        if keys is not None:
            keys = ",".join(keys)
            query_parameters['keys'] = self._serialize.query('keys', keys, 'str')
        response = self._send(http_method='GET',
                              location_id='4976a71a-4487-49aa-8aab-a1eda469037a',
                              version='5.1-preview.1',
                              route_values=route_values,
                              query_parameters=query_parameters)
        return self._deserialize('[ProjectProperty]', self._unwrap_collection(response))
GetProjectProperties.
        [Preview API] Get a collection of team project properties.
        :param str project_id: The team project ID.
        :param [str] keys: A comma-delimited string of team project property names. Wildcard characters ("?" and "*") are supported. If no key is specified, all properties will be returned.
        :rtype: [ProjectProperty]