'Constructor.
item_type - string that helps templates know how to render this item.
rec_src - code that lets us track where the rec originally came from,
useful for comparing performance of data sources or algorithms
sr and link are required
comment is optional
See r2.lib.recommender for valid values of item_type and rec_src.'

def __init__(self, item_type, rec_src, sr, link, comment=None):

    self.sr = sr
    self.link = link
    self.comment = comment
    self.type = item_type
    self.src = rec_src
    Templated.__init__(self)
