Cannot change values in PowerPoint Shape.Adjust.Item object

I am receiving an unexpected error message when attempting to programmatically adjust the beginning and ending angles of the arc shape in PowerPoint.

Example code that produces the error follows. Note that I ran this code with an already-open instance of PowerPoint and with version 305 of pywin32.

import win32com.client as win32 # Import pywin32

ppt = win32.gencache.EnsureDispatch('PowerPoint.Application') # Connect to PowerPoint application
shp = ppt.ActiveWindow.View.Slide.Shapes.AddShape(25, 200, 200, 100, 100) # Create an arc shape
shp.Adjustments.Item(1) = -45 # Try to adjust the starting angle of the arc (the first yellow circle)

This produces the following error message:

shp.Adjustments.Item(1) = -45 # Try to adjust the starting angle of the arc (the first yellow circle)
    ^
SyntaxError: cannot assign to function call here. Maybe you meant '==' instead of '='?

Based on this documentation, one should be able to adjust the values of Adjustments.Item(1) and .Item(2). I attempted the same task within PowerPoint's native VBA interface and did not run into any trouble. The VBA code follows:

Sub adj()

    Dim startAngle As Double, finishAngle As Double

    startAngle = InputBox("Select the starting angle (relative to the x-axis, counterclockwise)", "Start Angle")
    finishAngle = InputBox("Select the finishing angle (relative to the x-axis, counterclockwise)", "End Angle")

    Set aw = Application.ActiveWindow
    Set sl = aw.Selection
    Set shp = aw.Selection.ShapeRange(1)

    With shp
        .Adjustments.Item(2) = startAngle
        .Adjustments.Item(1) = finishAngle
    End With

End Sub

mhammond / pywin32

Cannot change values in PowerPoint Shape.Adjust.Item object #2021