Auto create blendshape from separate maya file

BlendshapeOrg.py

import os
import maya.cmds as cmds
import pymel.core as pm

currentFilePath = cmds.file(query=True, location=True)
subFolderName = "Blendshapes"
subFolderPath = os.path.join(os.path.dirname(currentFilePath), subFolderName)
blendshapeNamespace = 'Blendshape'
mainHead = None
targetShapes = []

def referenceMayaFilesFromFolder():
    try:
        # Get all maya files in subfolder and reference them
        fileList = os.listdir(subFolderPath)
        for fileName in fileList:
            if fileName.endswith('.ma') or fileName.endswith('.mb'):
                filePath = os.path.join(subFolderPath, fileName)
                cmds.file(filePath, reference=True, namespace=blendshapeNamespace)
    except:
        print ("No blendshape folder")

def listBlendshapes():
    for node in pm.ls(sl=True):
        print(node.listHistory(pruneDagObjects=True, type='blendShape'))

def removeBlendShapes():
    global mainHead
    # TODO: Change this later, currently done on objects in selection
    selectedObjects = cmds.ls(selection=True)
    # List all deformers applied to the selected object
    for selectedObject in selectedObjects:
        # TODO: Add better check on this. Set selected object as baseMesh
        mainHead = selectedObject
        deformers = cmds.listHistory(selectedObject)
        for deformer in deformers:
            if cmds.nodeType(deformer) == "blendShape":
                cmds.delete(deformer)
        cmds.select(clear=True)

def assignBlendshapes():
    print ("Blendshape assign")
    cmds.select(mainHead)
    blendshapeNode = cmds.blendShape(targetShapes, mainHead)[0]
    cmds.rename(blendshapeNode, "Blendshapes")

def getReferencedBlendshapes():
    global targetShapes
    # Get all referenced nodes in the scene
    references = pm.listReferences()
    refInNamespace = [ref for ref in references if ref.namespace == blendshapeNamespace]
    for ref_node in refInNamespace:
        print (ref_node)
        for c in ref_node.nodes():      
            # TODO: there's got to be better way than casting this to string
            if ("BS_" in str(c)) and ("Shape" not in str(c)):              
                cmds.select(str(c), add=True)
                targetShapes.append(c)

def removeAllReferences():
    # List all referenced files in the scene
    referencedFiles = cmds.file(q=True, r=True)
    # Unload and remove each referenced file
    for referencedFile in referencedFiles:
        cmds.file(referencedFile, unloadReference=True)        
        cmds.file(referencedFile, removeReference=True)

def runThis():
    removeBlendShapes()
    removeAllReferences()
    referenceMayaFilesFromFolder()
    getReferencedBlendshapes()
    assignBlendshapes()
    # Once all done remove all references again
    removeAllReferences()

runThis()