Python in ArcGIS: How to add a space between upper and lowercase letters in TOC

Question

I'd like to use python to update the TOC by adding a space (white space) for layer names that are like this: "BoundaryBuffer" or "WaterEdge" and replace them with "Boundary Buffer" or "Water Edge".

I'm new to python and could use some assistance so far I've gotten to this but I can't get it to work correctly:

    import arcpy
>>> import re
>>> mxd = arcpy.mapping.MapDocument("CURRENT")
>>> df = arcpy.mapping.ListDataFrames(mxd)[0]
>>> layers = arcpy.mapping.ListLayers (mxd)
>>> for lyr in layers:
...     re.findall('[A-Z][a-z]*', lyr.name)
...     arcpy.RefreshTOC()

I've looked at this post as well but I don't know how to integrate it with lyr.name in ArcGIS.

EDIT: I solved it myself! If anyone is interested or wants to comment:

import arcpy
... import re
... mxd = arcpy.mapping.MapDocument("CURRENT")
... df = arcpy.mapping.ListDataFrames(mxd)[0]
... layers = arcpy.mapping.ListLayers (mxd)
... for lyr in layers:
...     tempName = re.sub(r'([a-z])([A-Z])', r'\1 \2', lyr.name)
...     lyr.name = tempName
...     arcpy.RefreshTOC()

Answer 1

import arcpy
import re
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)[0]
layers = arcpy.mapping.ListLayers (mxd)
for lyr in layers:
    tempName = re.sub(r'([a-z])([A-Z])', r'\1 \2', lyr.name)
    lyr.name = tempName
    arcpy.RefreshTOC()