What does a multi-line where clause look like? I couldn't find an example, especially of a complex where clause, possibly using exists as one of the lines.
It's a pity the from keyword needs to be in single quotation marks. I was trying to think of an alternative (e.g. source), but then it wouldn't have the same syntax as SQL. A leading underscore would be better IMHO: _from. Python uses leading underscores in this situation.
