関連ワード:  python if string case insensitive    python check string case insensitive    python if string contains case insensitive    python if string equals case insensitive    python check string equality case insensitive    python if string in list case insensitive    python if substring in string case insensitive    python check if string contains case insensitive    python check if string in string case insensitive    python check if word in string case insensitive