给定一堂课：

from django.db import models

class Person(models.Model):
    name = models.CharField(max_length=20)

是否有可能（如果有的话）拥有一个基于动态参数进行过滤的QuerySet？例如：

 # Instead of:
 Person.objects.filter(name__startswith='B')
 # ... and:
 Person.objects.filter(name__endswith='B')

 # ... is there some way, given:
 filter_by = '{0}__{1}'.format('name', 'startswith')
 filter_value = 'B'

 # ... that you can run the equivalent of this?
 Person.objects.filter(filter_by=filter_value)
 # ... which will throw an exception, since `filter_by` is not
 # an attribute of `Person`.