'Initialize a new instance.
`field\' is an unparsed address header field, containing
one or more addresses.'

def __init__(self, field):

    self.specials = '()<>@,:;."[]'
    self.pos = 0
    self.LWS = '     DCTB '
    self.CR = '\r\n'
    self.FWS = (self.LWS + self.CR)
    self.atomends = ((self.specials + self.LWS) + self.CR)
    self.phraseends = self.atomends.replace('.', '')
    self.field = field
    self.commentlist = []
