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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def list_themes_user():
 """List user theme files."""

    themes = [*os.scandir(os.path.join(CONF_DIR, "colorschemes/dark/")),
              *os.scandir(os.path.join(CONF_DIR, "colorschemes/light/"))]
    return [t for t in themes if os.path.isfile(t.path)]