id	summary	reporter	owner	description	type	status	priority	component	severity	resolution	keywords	cc
169	PyYAML fails to load mapping keys of sequence type	sedie@…	xi	"The following YAML code is taken directly from an example given in the YAML 1.1 specification and fails to load with PyYAML, giving the error message: `found unacceptable key (unhashable type: 'list')`.

{{{
---
? - Detroit Tigers
  - Chicago cubs
:
  - 2001-07-23

? [ New York Yankees,
    Atlanta Braves ]
: [ 2001-07-02, 2001-08-12,
    2001-08-14 ]
...
}}}

The problem most likely arises because Python lists are not hashable and cannot be used as dict keys.  A possible solution may be to detect this special case and coerce YAML !!seq types to Python tuples before constructing the dictionaries that they are a part of.
"	defect	closed	normal	pyyaml	normal	wontfix