An error is generated when specifying 'NONE' as the workspace_type in the ArcPy mapping method replaceDataSource

Description

The ArcPy mapping module provides two replaceDataSource methods: Layer.replaceDataSource and TableView.replaceDataSource.

'NONE' is a valid value for the workspace_type parameter. When 'NONE' is specified, the workspace type native to the Layer or TableView being worked with should be used by the application. Instead, an error is returned.

Cause

This is a known issue at ArcGIS 10. For updates on the status, use bug number NIM058294.

Workaround

Code:
import arcpy
mxd = arcpy.mapping.MapDocument(r"C:\Project\Project.mxd")
for lyr in arcpy.mapping.ListBrokenDataSources(mxd):
    if lyr.supports("DATASOURCE"):
        if lyr.dataSource == r"C:\Project\Data\Transportation.gdb\MajorRoads":
            lyr.replaceDataSource(r"C:\Project\Data\Transportation.gdb", "NONE", "Highways")
            lyr.name = "Highways"
mxd.saveACopy(r"C:\Project\Project2.mxd")
del mxd

Code:
import arcpy
mxd = arcpy.mapping.MapDocument(r"C:\Project\Project.mxd")
for lyr in arcpy.mapping.ListBrokenDataSources(mxd):
    if lyr.supports("DATASOURCE"):
        if lyr.dataSource == r"C:\Project\Data\Transportation.gdb\MajorRoads":
            lyr.replaceDataSource(r"C:\Project\Data\Transportation.gdb", "FILEGDB_WORKSPACE", "Highways")
            lyr.name = "Highways"
mxd.saveACopy(r"C:\Project\Project2.mxd")
del mxd