Class AtomsInRingError

              object --+                
                       |                
exceptions.BaseException --+            
                           |            
        exceptions.Exception --+        
                               |        
        exceptions.StandardError --+    
                                   |    
               exceptions.ValueError --+
                                       |
                                      AtomsInRingError

Raised by Structure.adjust() when atoms are in a ring, so adjustment can't be made without distorting the structure.