code: def update(self, *a, **ka):
          
          prefix = ''
          if a and isinstance(a[0], basestring):
              prefix = a[0].strip('.') + '.'
              a = a[1:]
          for key, value in dict(*a, **ka).items():
              self[prefix + key] = value
docs: If the first parameter is a string, all keys are prefixed with this
              namespace. Apart from that it works just as the usual dict.update().
  
              >>> c = ConfigDict()
              >>> c.update('some.namespace', key='value')