Hello,
I am trying to put together a little script that would convert a line to a curve.
There may be a simpler way to do it but, the way I found looks like this:
Problem is I can’t figure out how to position the offCurve (control points) correctly. Any help would be greatly appreciated.

def getDist(a_list):
		if a_list:
			return max(a_list) - min(a_list)
		else:
			return 0

def convertToCurve():
	reference_glyph = CurrentGlyph()
	if reference_glyph and reference_glyph.selection != []:
		reference_glyph.prepareUndo()
		for contourIndex in range(len(reference_glyph.contours)):
			reference_contour = reference_glyph.contours[contourIndex]
			a_list_x = []
			a_list_y = []
			for i in range(len(reference_contour.segments)):
				reference_segment = reference_contour[i]
				if reference_segment.selected and reference_segment.type == "line":
					#last point of previous segment
					initPoint = reference_contour[i-1][0]
					print initPoint
					#end point of current segment
					endPoint = reference_contour[i][0]
					print endPoint
					
					a_list_x = [initPoint.x, endPoint.x]
					a_list_y = [initPoint.y, endPoint.y]
					firstThird_x = int(getDist(a_list_x) / 3)
					firstThird_y = int(getDist(a_list_y) / 3)
					#print initPoint, endPoint
					print firstThird_x, firstThird_y

					reference_segment.type = "curve"
					print reference_contour[i].points
					reference_contour[i].points[0].x = initPoint.x + firstThird_x
					reference_contour[i].points[0].y = initPoint.y + firstThird_y
					reference_contour[i].points[1].x = endPoint.x - firstThird_x
					reference_contour[i].points[1].y = endPoint.y  - firstThird_y
		reference_glyph.update()