def proximity_metric(self, a, b):
<EOL>res = <NUM_LIT:1><EOL>for ap, bp, n in zip(a.path_parts, b.path_parts, list(range(<NUM_LIT:4>))):<EOL><INDENT>res += ap == bp<EOL>if n >= <NUM_LIT:3>:<EOL><INDENT>break<EOL><DEDENT><DEDENT>return res<EOL>
Return the weight of the dependency from a to b. Higher weights
           usually have shorter straighter edges. Return 1 if it has normal
           weight. A value of 4 is usually good for ensuring that a related
           pair of modules are drawn next to each other.

           Returns an int between 1 (unknown, default), and 4 (very related).