a = b = c

[Yoriz]

Documentation » The Python Language Reference » 7.2. Assignment statements

assignment_stmt ::=  (target_list "=")+ (starred_expression | yield_expression)
An assignment statement evaluates the expression list (remember that this can be a single expression or a comma-separated list, the latter yielding a tuple) and assigns the single resulting object to each of the target lists, from left to right.