SQLAlchemy Relationships fail when using secondary Table

[floan]

Hey! Thanks for your great work on this!

I've queried SQLAlchemy Relationships with this library which works just fine, but fails when I use a secondary table. Example:

class Account():
    ...
    practice = relationship("Practice", secondary="user_practice", back_populates="accounts", uselist=False)


class Practice():
    ...
    accounts = relationship("Account", secondary="user_practice", back_populates="practice")

user_practice = Table(
    ...
    Column("account_id", ForeignKey("account.id", ondelete="CASCADE"), primary_key=True, unique=True),
    Column("practice_id", ForeignKey("practice.id", ondelete="CASCADE"), primary_key=True, index=True),
)

My query is something like this:

{
    accounts {
        edges {
            node {
                practice {
                    id
                }
            }
        }
    }
}

The library tries to look for account_id in the Practice table rather than the secondary table. I've also attached part of a stack trace below:

  File "/home/vscode/.local/lib/python3.11/site-packages/strawberry_sqlalchemy_mapper/mapper.py", line 420, in resolve
    related_objects = await loader.loader_for(relationship).load(
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vscode/.local/lib/python3.11/site-packages/strawberry/dataloader.py", line 251, in dispatch_batch
    values = await loader.load_fn(keys)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/workspace/backend/routers/graphql/mapper.py", line 109, in load_fn
    loaded = await loader.load_many(keys)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vscode/.local/lib/python3.11/site-packages/strawberry/dataloader.py", line 251, in dispatch_batch
    values = await loader.load_fn(keys)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vscode/.local/lib/python3.11/site-packages/strawberry_sqlalchemy_mapper/loader.py", line 49, in load_fn
    grouped_keys[group_by_remote_key(row)].append(row)
                 ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/vscode/.local/lib/python3.11/site-packages/strawberry_sqlalchemy_mapper/loader.py", line 41, in group_by_remote_key
    [
  File "/home/vscode/.local/lib/python3.11/site-packages/strawberry_sqlalchemy_mapper/loader.py", line 42, in <listcomp>
    getattr(row, remote.key)
AttributeError: 'Practice' object has no attribute 'account_id'

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