docstr: Returns the Table's index column, or ``None`` if an index is not
  specified by the user.
docstr_tok: ["Returns","the","Table","'s","index","column",",","or","``","None","``","if","an","index","is","not","specified","by","the","user","."]
code: def get_index(self):
      """Returns the Table's index column, or ``None`` if an index is not
      specified by the user."""
      return self._index
  
imports: from datetime import date, datetime
  from ..core.exception import PerspectiveError
  from ._accessor import _PerspectiveAccessor
  from ._callback_cache import _PerspectiveCallBackCache
  from ._date_validator import _PerspectiveDateValidator
  from ._state import _PerspectiveStateManager
  from ._utils import _dtype_to_pythontype, _dtype_to_str, _parse_expression_inputs, _str_to_pythontype
  from .libpsppy import make_table, update_table, str_to_filter_op, t_dtype, t_filter_op, t_op, validate_expressions
  from .view import View
label_desc: Use image node_id 4 for calling the Table obj's underlying member method code with example usage: obj.get_index() and returns: self