id,summary,reporter,owner,description,type,status,component,version,severity,resolution,keywords,cc,stage,has_patch,needs_docs,needs_tests,needs_better_patch,easy,ui_ux 23572,Exception on Custom Lookups when right value is None.,maherma-adg,,"For my current project I need generate a complex queryset filter and I decide implement as custom lookup. I got the [https://docs.djangoproject.com/en/1.7/howto/custom-lookups/, example] as base to create custom lookup, but during test, this expression: `data = Rsce.filter(duration__ne = None)` throws an exception. Any other expression runs smoothly. Looking into code exception are thrown in this piece of code: {{{ if value is None: if lookups[-1] not in ('exact', 'iexact'): raise ValueError(""Cannot use None as a query value"") }}} IMHO the check in lookups must be avoided on custom lookups, allowing them to manage None values by themselves.",Bug,closed,"Database layer (models, ORM)",1.7,Normal,fixed,"custom lookup, db",,Accepted,0,0,0,0,0,0