code: def crop(self, lat, lon, var):
          
          dims, idx = cropIndices(self.dims, lat, lon)
          subset = {}
          for v in var:
              subset = {v: self.ncs[0][v][idx['yn'], idx['xn']]}
          return subset, dims
docs: Crop a subset of the dataset for each var
  
              Given doy, depth, lat and lon, it returns the smallest subset
                that still contains the requested coordinates inside it.
  
              It handels special cases like a region around greenwich and
              the international date line.
  
              Accepts 0 to 360 and -180 to 180 longitude reference.
  
              It extends time and longitude coordinates, so simplify the use
                 of series. For example, a ship track can be requested with
                 a longitude sequence like [352, 358, 364, 369, 380].