Python MRO is based on C3, the MRO built for the Dylan programming language (http://opendylan.org). The reference document, written by Michele Simionato, can be found at http://www.python.org/download/releases/2.3/mro. It describes how C3 builds the linearization of a class, also called precedence, which is an ordered list of the ancestors. This list is used to seek an attribute. The C3 algorithm is described in more detail later in this section.
The MRO change was made to resolve an issue introduced with the creation of a common base type (that is, object type). Before the change to the C3 linearization method, if a class had two ancestors (refer to Figure 1), the order in which methods were ...
