def __init__(self, attr=None, value=None, pos=<NUM_LIT:0>):
self.attr = attr<EOL>self.value = value<EOL>self.pos = pos<EOL>
Arguments

attr
    Should reference some attribute of the referenced Node
value
    Some value that will be assigned to this token for use in
    the production of chunks
pos
    The index to be passed to Token.getpos for the correct
    index for the given token map entry.  The text element will
    be used for the lookup first, and typically the correct
    position will be reported on the 0th entry, however for
    certain Node types multiple entries may be use, and so for
    that situation the pos will need to be explicitly specified,
    increment for each time that the exact value may be
    generated through the execution of the rule description for
    a given Node.