Polymorphic Filtering (for fields in inherited classes) enhance

Sorry in advance I wanted to label this an enhancement but the labels aren't showing up.

`class Project(PolymorphicModel):
topic = models.CharField(max_length=30)

class ArtProject(Project):
artist = models.CharField(max_length=30)

class ResearchProject(Project):
supervisor = models.CharField(max_length=30)

class ScienceProject(Project):
supervisor = models.CharField(max_length=30)
other_field = models.BooleanField()`

I may have missed this in the documentation but if two inherited models share a common field in this case the supervisor field shared by the Research and Science project is there a cleaner way to make a query on supervisor other than.

results = Project.objects.filter(Q(ResearchProject___supervisor="Bob") | Q(ScienceProject___supervisor="Bob"))

something like

results = Project.objects.instance_of(ResearchProject, ScienceProject).filter(supervisor="Bob")

or even better would be

results = Project.objects.filter(supervisor="Bob")

Start by reproducing the Project, ResearchProject, and ScienceProject model examples and compare the existing Q-based query with the proposed Project.objects.instance_of(...).filter(supervisor="Bob") forms. Investigate the polymorphic manager and Django ORM filtering behavior. Done means a shared inherited field can be filtered without manually OR-ing subtype-specific paths, with behavior covered by tests.