code: def splitPrefix(name):
      
      if isinstance(name, str) and ':' in name:
          return tuple(name.split(':', 1))
      else:
          return (None, name)
docs: Split the name into a tuple (I{prefix}, I{name}).  The first element in
      the tuple is I{None} when the name does't have a prefix.
      @param name: A node name containing an optional prefix.
      @type name: basestring
      @return: A tuple containing the (2) parts of I{name}
      @rtype: (I{prefix}, I{name})