code: def _dataframe_to_vertex_list(df):
      """
      Convert dataframe into list of vertices, assuming that vertex ids are stored in _VID_COLUMN.
      """
      cols = df.columns
      if len(cols):
          assert _VID_COLUMN in cols, (
              "Vertex DataFrame must contain column %s" % _VID_COLUMN
          )
          df = df[cols].T
          ret = [Vertex(None, _series=df[col]) for col in df]
          return ret
      else:
          return []
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  from .._connect import main
  from .sframe import SFrame
  from .sarray import SArray
  from .gframe import GFrame, VERTEX_GFRAME, EDGE_GFRAME
  from .._cython.cy_graph import UnityGraphProxy
  from .._cython.context import debug_trace
  from ..util import _is_non_string_iterable, _make_internal_url
  from .._deps import pandas
  from .._deps import HAS_PANDAS
  import inspect
  import copy
  import sys
label_desc: Use image node_id 6 for calling a global function with example usage: _dataframe_to_vertex_list(df) and returns: ret, list