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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 run_cleanup(build_ext_cmd):
 """Cleanup after ``BuildFortranThenExt.run``. For in-place builds, moves the built shared library into the source directory. """

    if not build_ext_cmd.inplace:
        return

    bezier_dir = os.path.join("src", "bezier")
    shutil.move(os.path.join(build_ext_cmd.build_lib, LIB_DIR), bezier_dir)
    shutil.move(os.path.join(build_ext_cmd.build_lib, DLL_DIR), bezier_dir)