def get_collapse_fns():
 return {'median': _collapse_to_median, 'first': _collapse_to_first, 'random': _collapse_to_random, 'sum': _collapse_to_sum, 'mean': _collapse_to_mean}

def get_collapse_fns ( ) : return { 'median' : _collapse_to_median , 'first' : _collapse_to_first , 'random' : _collapse_to_random , 'sum' : _collapse_to_sum , 'mean' : _collapse_to_mean }
return lookup of functions that can be used with biom .