code: def appendGuideline(self, position=None, angle=None, name=None, color=None, guideline=None):
          
          identifier = None
          if guideline is not None:
              guideline = normalizers.normalizeGuideline(guideline)
              if position is None:
                  position = guideline.position
              if angle is None:
                  angle = guideline.angle
              if name is None:
                  name = guideline.name
              if color is None:
                  color = guideline.color
              if guideline.identifier is not None:
                  existing = set([g.identifier for g in self.guidelines if g.identifier is not None])
                  if guideline.identifier not in existing:
                      identifier = guideline.identifier
          position = normalizers.normalizeCoordinateTuple(position)
          angle = normalizers.normalizeRotationAngle(angle)
          if name is not None:
              name = normalizers.normalizeGuidelineName(name)
          if color is not None:
              color = normalizers.normalizeColor(color)
          identifier = normalizers.normalizeIdentifier(identifier)
          guideline = self._appendGuideline(position, angle, name=name, color=color, identifier=identifier)
          guideline.font = self
          return guideline
docs: Append a new guideline to the font.
  
              >>> guideline = font.appendGuideline((50, 0), 90)
              >>> guideline = font.appendGuideline((0, 540), 0, name="overshoot",
              >>> color=(0, 0, 0, 0.2))
  
          **position** must be a :ref:`type-coordinate`
          indicating the position of the guideline.
          **angle** indicates the :ref:`type-angle` of
          the guideline. **name** indicates the name
          for the guideline. This must be a :ref:`type-string`
          or ``None``. **color** indicates the color for
          the guideline. This must be a :ref:`type-color`
          or ``None``. This will return the newly created
          :class:`BaseGuidline` object.
  
          ``guideline`` may be a :class:`BaseGuideline` object from which
          attribute values will be copied. If ``position``, ``angle``, ``name``
          or ``color`` are specified as arguments, those values will be used
          instead of the values in the given guideline object.