Plone 5.2.1/zc.relation - What is causing a relation query based on from_attribute/to_id to return nothing?

I'm trying to make a query using the relation catalog with from_attribute and to_id as the parameters.

I have a content type called Contract, which has a RelationChoice field called 'project'.

from import CatalogSource
from z3c.relationfield.schema import RelationChoice

class IContract(model.Schema):
    project = RelationChoice(title=u"Project",
                                            description=u"Set in events",

and I have a content type called Project, which is tied to the Contract.

from zope.intid.interfaces import IIntIds
from zc.relation.interfaces import ICatalog
from zope.component import getUtility

class IProject(model.Schema):

class Project(Item):

    def get_contract(self):
        intids = getUtility(IIntIds)
        catalog = getUtility(ICatalog)
        from_attribute = 'project'
        to_id = intids.getId(self)
        relations = catalog.findRelations(query)
        objs = [i.to_object for i in relations]
        print(objs)  #Empty list
        if objs:
            return objs[0]
            return None

In my view template for, I have

<div tal:define="contract python:context.get_contract()">

When I do this, the print statement in get_contract prints an empty list.

What am I doing wrong? Is intids.getId(self) not getting the right int id or is 'project' not being added? Or perhaps I'm getting the to/from backwards?