code: def exists(cls, query=None, path=None, **kwargs):
          
          if query is None and len(kwargs) > 0:
              query = kwargs
          if query is None:
              return False
          return cls.db(path).find_one(query) is not None
docs: Like __init__ but simply returns a boolean as to whether or not the
          object exists, rather than returning the whole object.
          
          NOTE: if you pass in a single argument to exists, this will
          match against ID_KEY.
          
          @param query: a dictionary specifying key-value pairs that the result
              must match.  If query is None, use kwargs in it's place
          @param path: the path of the database to query, in the form
              "database.colletion"; pass None to use the value of the
              PATH property of the object
          @param **kwargs: used as query parameters if query is None
          
          @raise Exception: if path and self.PATH are None; the database path
              must be defined in at least one of these