code: def _call(self, x, out=None):
          
          # TODO: pass reasonable options on to the interpolator
          def linear(arg, out=None):
              """Interpolating function with vectorization."""
              if is_valid_input_meshgrid(arg, self.grid.ndim):
                  input_type = 'meshgrid'
              else:
                  input_type = 'array'
  
              interpolator = _LinearInterpolator(
                  self.grid.coord_vectors, x, input_type=input_type)
  
              return interpolator(arg, out=out)
  
          return self.range.element(linear, vectorized=True)
docs: Return ``self(x[, out])``.