list file path from usd shade

node = hou.pwd()
stage = node.editableStage()

# Add code to modify the stage.
# Use drop down menu to select examples.
from pxr import Usd, UsdShade

def find_unique_asset_paths(stage, prim_path):
    # Open the stage and get the root prim
    root_prim = stage.GetPrimAtPath(prim_path)
    if not root_prim:
        raise ValueError(f"Prim path '{prim_path}' does not exist in the stage.")

    # Set to store unique asset paths
    unique_asset_paths = set()

    # Recursive function to traverse prims
    def traverse_prim(prim):
        for child in prim.GetAllChildren():
            # Check if prim is a UsdShadeShader
            if child.IsA(UsdShade.Shader):
                shader = UsdShade.Shader(child)
                # Check if the shader has an attribute called inputs:file
                file_attr = shader.GetInput("file")
                if file_attr:
                    # Add the value to the set of unique paths
                    asset_path = file_attr.Get()
                    #if isinstance(asset_path, str):
                    unique_asset_paths.add(asset_path.path)
            # Traverse further into children
            traverse_prim(child)

    # Start traversal from the root prim
    traverse_prim(root_prim)

    # Log the unique asset paths
    print("Unique USD Asset Paths:")
    for path in unique_asset_paths:
        print(path)

    return list(unique_asset_paths)

# Usage example

prim_path = "/master/shading"


unique_paths = find_unique_asset_paths(stage, prim_path)