Define/overwrite the line- and column index of marker ``markerID``.

        The default marker has ``markerID=0`` by convention.

        If ``line`` and/or ``col`` are not provided they are substituted
        with the values of the current cursor position.

        ..note: ``line`` and ``col`` are not range checked. They can therefore
                take on arbitrary values (even negative ones) that do not
                denote a valid position in the document.

        |Args|

        * ``markerID`` (**object**): arbitrary Python object that is
          internally used as a dictionary.
        * ``line`` (**int**): an integer specifying the line
          number of the marker.
        * ``col`` (**int**): an integer specifying the column
          number of the marker.

        |Returns|

        * **None**

        |Raises|

        * **None**

def qteSetMark(self, markerID=0, line: int=None, col: int=None):
        """
        Define/overwrite the line- and column index of marker ``markerID``.

        The default marker has ``markerID=0`` by convention.

        If ``line`` and/or ``col`` are not provided they are substituted
        with the values of the current cursor position.

        ..note: ``line`` and ``col`` are not range checked. They can therefore
                take on arbitrary values (even negative ones) that do not
                denote a valid position in the document.

        |Args|

        * ``markerID`` (**object**): arbitrary Python object that is
          internally used as a dictionary.
        * ``line`` (**int**): an integer specifying the line
          number of the marker.
        * ``col`` (**int**): an integer specifying the column
          number of the marker.

        |Returns|

        * **None**

        |Raises|

        * **None**
        """

        # Query the line- and column number unless provided.
        if (line is None) and (col is None):
            line, col = self.getCursorPosition()
        elif line is None:
            line, _ = self.getCursorPosition()
        elif col is None:
            _, col = self.getCursorPosition()
        else:
            pass

        self.qteMarkers[markerID] = (line, col)
        return (line, col)