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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 read_catalog_info_yaml(self, splitkey):
 """ Read the yaml file for a particular split key """

        catalog_info_yaml = self._name_factory.catalog_split_yaml(sourcekey=splitkey,
                                                                  fullpath=True)
        yaml_dict = yaml.safe_load(open(catalog_info_yaml))
        # resolve env vars
        yaml_dict['catalog_file'] = os.path.expandvars(yaml_dict['catalog_file'])
        yaml_dict['catalog_extdir'] = os.path.expandvars(yaml_dict['catalog_extdir'])
        return yaml_dict