code: def _field_accessor(name, docstring=None, min_cftime_version='0.0'):
      
  
      def f(self, min_cftime_version=min_cftime_version):
          import cftime
  
          version = cftime.__version__
  
          if LooseVersion(version) >= LooseVersion(min_cftime_version):
              return get_date_field(self._data, name)
          else:
              raise ImportError('The {!r} accessor requires a minimum '
                                'version of cftime of {}. Found an '
                                'installed version of {}.'.format(
                                    name, min_cftime_version, version))
  
      f.__name__ = name
      f.__doc__ = docstring
      return property(f)
docs: Adapted from pandas.tseries.index._field_accessor