def get_bls(tree_path):
# clean the tree of any support values, so we're left only with BLs
bls = []
t = Tree()
t.read_from_path( tree_path, "newick" )
i = t.level_order_edge_iter()
while True:
try:
e = i.next() # in Python 2.x
len = e.length
if len != None:
bls.append( len )
except StopIteration:
break
return bls
