kowey/educe — pull request #12 by moreymat (2014-10-28 13:15:57+00:00)
Title: FIX rename Span.len() to Span.length()

`len` is a reserved method name, usually implemented as `__len__(self)` and called as `len(x)`.
A minimal fix is to rename Span.len() to Span.length().