Intake Catalog - Converter kwarg

Question

Is it possible to include the "converter" kwarg in an intake catalog? I have a bunch of csv files with lat / lon coordinates with "N" and "S" suffixes. Something along the lines of:

sources:
  Source1:
    description: A Description
    driver: csv
    args:
      urlpath: [path_to_file.csv]
      csv_kwargs:
        converters: {'LATITUDE N/S':lambda x: float(x[0:-1])}

Errors with

ParserError: while parsing a flow mapping
  in "<unicode string>", line 50, column 21:
            converters: {'LATITUDE N/S':lambda x:float(x ... 
                            ^
    expected ',' or '}', but got '['
      in "<unicode string>", line 50, column 53:
         ... {'LATITUDE N/S':lambda x:float(x[0:-1])}

Essentially, how can I embed a simply python lambda function in the catalog?

Thanks!