class_docstr: A uniform accessor that wraps data/schemas of varying formats with a
  common :func:`marshal` function.
docstr: Get the element at the specified column name and row index.
  
  If the element does not exist, return None.
  
  Args:
      column_name (str)
      ridx (int)
  
  Returns:
      object or None
docstr_tok: ["Get","the","element","at","the","specified","column","name","and","row","index",".","If","the","element","does","not","exist",",","return","None",".","Args",":","column_name","(","str",")","ridx","(","int",")","Returns",":","object","or","None"]
code: def get(self, column_name, ridx):
      """Get the element at the specified column name and row index.
  
      If the element does not exist, return None.
  
      Args:
          column_name (str)
          ridx (int)
  
      Returns:
          object or None
      """
      val = None
      try:
          if self._format == 0:
              return self._data_or_schema[ridx][column_name]
          elif self._format == 1:
              return self._data_or_schema[column_name][ridx]
          else:
              raise NotImplementedError()
          return val
      except (KeyError, IndexError):
          return None
  
imports: from distutils.util import strtobool
  from math import isnan
  import numpy
  import pandas
  from ..core.data import deconstruct_numpy, deconstruct_pandas, make_null_mask
  from ..core.data.pd import _parse_datetime_index
  from ..core.exception import PerspectiveError
  from ._date_validator import _PerspectiveDateValidator
  from .libpsppy import t_dtype
label_desc: Use image node_id 8 for calling the _PerspectiveAccessor obj's underlying member method code with example usage: obj.get(column_name, ridx) and returns: val, self, None, self