docs: def get_time_variable(ds):
      '''
      Returns the likeliest variable to be the time coordiante variable
  
      :param netCDF4.Dataset ds: An open netCDF4 Dataset
      '''
      for var in ds.variables:
          if getattr(ds.variables[var], 'axis', '') == 'T':
              return var
      else:
          candidates = ds.get_variables_by_attributes(standard_name='time')
          if len(candidates) == 1:
              return candidates[0].name
          else:  # Look for a coordinate variable time
              for candidate in candidates:
                  if candidate.dimensions == (candidate.name,):
                      return candidate.name
  
      return None