def lookup_signum(name):
uname = name.upper()<EOL>if (uname.startswith('<STR_LIT>') and hasattr(signal, uname)):<EOL><INDENT>return getattr(signal, uname)<EOL><DEDENT>else:<EOL><INDENT>uname = "<STR_LIT>"+uname<EOL>if hasattr(signal, uname):<EOL><INDENT>return getattr(signal, uname)<EOL><DEDENT>return None<EOL><DEDENT>return<EOL>
Find the corresponding signal number for 'name'. Return None
    if 'name' is invalid.