'Delete a value from the mapping using the key.'                       

'Set a new item in the mapping.'                                       

'delete all items'                                                     

'''remove specified key and return the corresponding value
        *args may contain a single default value, or may not be suppli\
ed.
        If key is not found, default is returned if given, otherwise 
        KeyError is raised'''                                          

'''remove and return some (key, value) pair as a
        2-tuple; but raise KeyError if mapping is empty'''             

'D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D'     

' Update D from E: for k in E.keys(): D[k] = E[k]'