      def _checkindex(self, index):
          "Checks the given index."
          sz = self.size
          if (sz < 1) or (index < 0) or (index >= sz):
              raise GEOSIndexError('invalid GEOS Geometry index: %s' % str(index))
  
      def _checkdim(self, dim):
          "Checks the given dimension."
          if dim < 0 or dim > 2:
              raise GEOSException('invalid ordinate dimension "%d"' % dim)
 
</s> remove         raise self._IndexError('invalid index: %s' % str(index))
 </s> add         raise IndexError('invalid index: %s' % str(index)) </s> remove 
    class _IndexError:
        The type of exception to be raise on invalid index [Optional]
 </s> add  </s> remove             except self._IndexError:
 </s> add             except IndexError: </s> remove                 self.assertRaises(GEOSIndexError, g.get_x)
 </s> add                 self.assertRaises(IndexError, g.get_x) </s> remove """
 This module houses the GEOS exceptions, specifically, GEOSException and
 GEOSGeometryIndexError.
"""


 </s> add 
            raise IndexError('invalid GEOS Geometry index: %s' % str(index))
      def _checkindex(self, index):
          "Checks the given index."
          sz = self.size
          if (sz < 1) or (index < 0) or (index >= sz):
            raise IndexError('invalid GEOS Geometry index: %s' % str(index))
  
      def _checkdim(self, dim):
          "Checks the given dimension."
          if dim < 0 or dim > 2:
              raise GEOSException('invalid ordinate dimension "%d"' % dim)
keep keep keep keep replace keep keep keep keep keep
 Fixed #25225 -- Simplified code to remove GEOSIndexError

The test is a regression for refs #4740 to show that the original
fix of GEOSIndexError is no longer needed. 
django/contrib/gis/geos/coordseq.py