def get_platform_variables(ds):
candidates = []<EOL>for variable in ds.variables:<EOL><INDENT>platform = getattr(ds.variables[variable], '<STR_LIT>', '<STR_LIT>')<EOL>if platform and platform in ds.variables:<EOL><INDENT>if platform not in candidates:<EOL><INDENT>candidates.append(platform)<EOL><DEDENT><DEDENT><DEDENT>platform = getattr(ds, '<STR_LIT>', '<STR_LIT>')<EOL>if platform and platform in ds.variables:<EOL><INDENT>if platform not in candidates:<EOL><INDENT>candidates.append(platform)<EOL><DEDENT><DEDENT>return candidates<EOL>
Returns a list of platform variable NAMES

:param netCDF4.Dataset ds: An open netCDF4 Dataset