Apply Symbology to Rasters using Arcpy Script

I have an ArcPy script to apply the symbology of one raster layer to all of the raster layers in the table of contents. I have used this script before with feature layers instead of raster layers, and it worked perfectly. Now when I run it, it runs continuously and it does not change the symbology of any of the raster layers in the table of contents. It does not give me any error messages; the window appears, saying that it successfully changed the symbology. Also, it works when I manually apply the symbology of one raster layer to the other layers in the table of contents. The script seems to iterate through the list without actually changing anything.