class_docstr: Line graph class
class_docstr_tok: ["Line","graph","class"]
docstr: Add extra values to fill the line
docstr_tok: ["Add","extra","values","to","fill","the","line"]
code: def _fill(self, values):
      """Add extra values to fill the line"""
      zero = self.view.y(
          min(max(self.zero, self._box.ymin), self._box.ymax)
      )
  
      # Check to see if the data has been padded with "none's"
      # Fill doesn't work correctly otherwise
      end = len(values) - 1
      while end > 0:
          x, y = values[end]
          if self.missing_value_fill_truncation == "either":
              if x is not None and y is not None:
                  break
          elif self.missing_value_fill_truncation == "x":
              if x is not None:
                  break
          elif self.missing_value_fill_truncation == "y":
              if y is not None:
                  break
          else:
              raise ValueError(
                  "Invalid value ({}) for config key "
                  "'missing_value_fill_truncation';"
                  " Use 'x', 'y' or 'either'".format(
                      self.missing_value_fill_truncation
                  )
              )
          end -= 1
  
      return [(values[0][0], zero)] + values + [(values[end][0], zero)]
  
file_path: pygal/pygal/graph/line.py
imports: from pygal.graph.graph import Graph
  from pygal.util import alter, cached_property, decorate
label_desc: Use image node_id 4 for calling the Line obj's underlying member method code with example usage: obj._fill(values) and returns: unknown