Return |FreeformBuilder| object to specify a freeform shape.

        The optional *start_x* and *start_y* arguments specify the starting
        pen position in local coordinates. They will be rounded to the
        nearest integer before use and each default to zero.

        The optional *scale* argument specifies the size of local coordinates
        proportional to slide coordinates (EMU). If the vertical scale is
        different than the horizontal scale (local coordinate units are
        "rectangular"), a pair of numeric values can be provided as the
        *scale* argument, e.g. `scale=(1.0, 2.0)`. In this case the first
        number is interpreted as the horizontal (X) scale and the second as
        the vertical (Y) scale.

        A convenient method for calculating scale is to divide a |Length|
        object by an equivalent count of local coordinate units, e.g.
        `scale = Inches(1)/1000` for 1000 local units per inch.

def build_freeform(self, start_x=0, start_y=0, scale=1.0):
        """Return |FreeformBuilder| object to specify a freeform shape.

        The optional *start_x* and *start_y* arguments specify the starting
        pen position in local coordinates. They will be rounded to the
        nearest integer before use and each default to zero.

        The optional *scale* argument specifies the size of local coordinates
        proportional to slide coordinates (EMU). If the vertical scale is
        different than the horizontal scale (local coordinate units are
        "rectangular"), a pair of numeric values can be provided as the
        *scale* argument, e.g. `scale=(1.0, 2.0)`. In this case the first
        number is interpreted as the horizontal (X) scale and the second as
        the vertical (Y) scale.

        A convenient method for calculating scale is to divide a |Length|
        object by an equivalent count of local coordinate units, e.g.
        `scale = Inches(1)/1000` for 1000 local units per inch.
        """
        try:
            x_scale, y_scale = scale
        except TypeError:
            x_scale = y_scale = scale

        return FreeformBuilder.new(self, start_x, start_y, x_scale, y_scale)