code: def _jcols(self, *cols):
          
          if len(cols) == 1 and isinstance(cols[0], list):
              cols = cols[0]
          return self._jseq(cols, _to_java_column)
docs: Return a JVM Seq of Columns from a list of Column or column names
  
          If `cols` has only one list in it, cols[0] will be used as the list.