No check for bind parameter values #514

Hi,

I'm using raw queries like that:

record = await db.fetch_one(
    query='select * from table_a where id = :id',
    values={
        # "id": 0
    })

If I don't provide bind parameter value (like that :id), bind parameter value is set to None and query executes successfully. I was expecting that an error will be thrown saying that I miss a value for the parameter.

Is there anything I'm missing?

databases[postgresql]==0.6.1