code: def load_error(self):
          
          usecols = []
          for v in self.error_columns:
              if v is None:
                  pass
              elif isinstance(v, int):
                  usecols.append(v)
              elif len(v) is 2:
                  for n in v: usecols.append(n)
          self.genfromtxt_args_error['usecols'] = tuple(usecols)
  
          array = numpy.genfromtxt(self.path, **self.genfromtxt_args_error)
  
          error = []
          for n, v in enumerate(self.error_columns):
              if v is None:
                  error.append(None)
              elif isinstance(v, int):
                  if len(usecols) is 1:
                      error.append(array * self.scale[n])
                  else:
                      error.append(array[0] * self.scale[n])
                      array = numpy.delete(array, (0), axis=(0))
              elif len(v) is 2:
                  error.append(array[0:2] * self.scale[n])
                  array = numpy.delete(array, (0, 1), axis=(0))
  
          return tuple(error)
docs: Loads error values from `scipy_data_fitting.Data.path` using [`numpy.genfromtxt`][1]
          and returns a two element tuple where each element is of a form described by
          cases 3 and 4 in `scipy_data_fitting.Data.error`.
  
          The columns to import are set by `scipy_data_fitting.Data.error_columns`.
  
          Values are scaled according to `scipy_data_fitting.Data.scale`.
  
          Arguments to [`numpy.genfromtxt`][1] are controlled
          by `scipy_data_fitting.Data.genfromtxt_args_error`.
  
          [1]: http://docs.scipy.org/doc/numpy/reference/generated/numpy.genfromtxt.html