code: def is_not_null_predicate(
      raw_crash, dumps, processed_crash, processor, key=''
  ):
      
      try:
          return bool(raw_crash[key])
      except KeyError:
          return False
docs: a predicate that converts the key'd source to boolean.
  
      parameters:
          raw_crash - dict
          dumps - placeholder in a fat interface - unused
          processed_crash - placeholder in a fat interface - unused
          processor - placeholder in a fat interface - unused