def __init__(self, query, entity):
    if (not query._primary_entity):
        query._primary_entity = self
    query._entities.append(self)
    self.entities = [entity]
    self.expr = entity
def __init__(self, query, entity):
    if (not query._primary_entity):
        query._primary_entity = self
    query._entities.append(self)
    self.entities = [entity]
    self.expr = entity