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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 clean(bld):
	'''removes the build files'''
	try:
		proj=Environment.Environment(Options.lockfile)
	except IOError:
		raise Utils.WafError('Nothing to clean (project not configured)')
	bld.load_dirs(proj[SRCDIR],proj[BLDDIR])
	bld.load_envs()
	bld.is_install=0
	bld.add_subdirs([os.path.split(Utils.g_module.root_path)[0]])
	try:
		bld.clean()
	finally:
		bld.save()