TypeError: 'str' object is not callable when using CreateShader()

Hello, I'm creating a plugin and part of what it does is create Redshift materials, but I seem to be getting this error when using the CreateShader() function. I tested graphos' example with the TextureSampler and it worked perfectly, but when I'm trying to use it within my fuction I'm getting an error.

Here's my function -

def createRedshiftMaterial(op,materials,name,texpath):
    rs = Redshift()
    RSMATERIAL_ID = 1000

    # Get BaseDocument
    doc = c4d.documents.GetActiveDocument()

    # Create RS Material
    c4d.CallCommand(1036759, 1000)

    mat = doc.SearchMaterial("RS Material")

    # Name it
    mat.SetName(name)

    #Assign Material
    rs.SetMat(doc.GetFirstMaterial())

    #Get default material node and output node
    listNode = rs.GetAllNodes()
    MatNode = None
    OutPutNode = None
    for node in listNode:
        if node.GetType() == "Output":
            OutPutNode = node
        elif node.GetType() == "Material":
            MatNode = node

    if not MatNode or not OutPutNode:
        return

    for texture in materials[name].keys():
        position = 0,0
        if texture == "Color Map":
            position = 200,500
            mat_input = c4d.REDSHIFT_SHADER_MATERIAL_DIFFUSE_WEIGHT

            # Create image path
        #imagePath = "%s\\%s.tga" %(str(texpath),materials[name][texture])

        if position[0] != 0:
            TextureNode = rs.CreateShader(rs.TexSampler, x=20, y=200)
            #TextureNode[c4d.REDSHIFT_SHADER_TEXTURESAMPLER_TEX0, c4d.REDSHIFT_FILE_PATH] = imagePath

            #Expose a paramter of the material
            MatNode.ExposeParameter(mat_input, c4d.GV_PORT_INPUT)

            #Connect Texture shader to the material
            rs.CreateConnection(TextureNode, MatNode, 0, 0)

            #Connect material shader to the output
            rs.CreateConnection(MatNode, OutPutNode, 0, 0)

            c4d.EventAdd()

    # Create Texture-Tag for our object
    textag = c4d.TextureTag()
    # Assign our material to the tag
    textag.SetMaterial(mat)
    # Set Texture-Tag Projection
    textag[c4d.TEXTURETAG_PROJECTION]=c4d.TEXTURETAG_PROJECTION_UVW
        # Assign material to our object
    op.InsertTag(textag)
    doc.InsertMaterial(mat)
    op.Message(c4d.MSG_UPDATE)
    c4d.EventAdd()

The error -

TextureNode = rs.CreateShader(rs.TexSampler, x=20, y=200)
File "<string>", line 350, in CreateShader
File "<string>", line 183, in _TestProperty
TypeError: 'str' object is not callable

gr4ph0s / C4D_RedshiftWrapper_API

TypeError: 'str' object is not callable when using CreateShader() #4