import re
 
test_str = ("(a) method in/to one's madness\n"
    "(all) by one's lonesome\n"
    "(as) tough as (old boot's)\n"
    " (at) any moment (now)   \n"
    "factors (in or into or out)        \n"
    " right-to-life\n"
    "all mouth (and no trousers/action)\n"
    "(it's a) small world\n"
    "  throw (someone) a bone ")
 
regex = r"[^\S\r\n]*\([^()]*\)"
result = "\n".join([x.strip() for x in re.sub(regex, "", test_str).splitlines()])
print (result)

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