class BackwardContextRange(object):
Undocumented
| Method | __init__ | 
    Undocumented | 
| Property | begin | 
    return the first included context (trace.Context) | 
  
| Property | end | 
    return the first excluded context (trace.Context) if available, `None` otherwise. | 
  
| Property | last | 
    return the last included context (trace.Context) | 
  
| Method | __reversed__ | 
    Undocumented | 
| Method | __len__ | 
    Undocumented | 
| Method | __iter__ | 
    Undocumented | 
| Method | __eq__ | 
    Undocumented | 
| Method | __str__ | 
    Undocumented | 
| Method | __repr__ | 
    Undocumented | 
| Method | format_as_html | 
    This method gets an html formatting string representation for this class instance. | 
| Instance Variable | _first | 
    Undocumented | 
| Instance Variable | _last | 
    Undocumented | 
| Method | _repr_html_ | 
    Representation used by Jupyter Notebook when an instance of this class is displayed in a cell. | 
return the first excluded context (trace.Context) if available, `None` otherwise.
_Optional[Context])