code: def _get_str_columns(sf):
      """
      Returns a list of names of columns that are string type.
      """
      return [
          name for name in sf.column_names() if sf[name].dtype == str
      ]
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import turicreate
  from turicreate.toolkits._internal_utils import _raise_error_if_not_sframe
  from turicreate.toolkits._model import CustomModel
  from turicreate.toolkits._model import PythonProxy
  from turicreate.toolkits._internal_utils import _toolkit_repr_print
  from turicreate.toolkits import text_analytics
label_desc: Use image node_id 3 for calling a global function with example usage: _get_str_columns(sf) and returns: unknown