let is_case_sensitive: bool = if let Ok(case_sensitive) = dotenvy::var("CASE_SENSITIVE") {
        match case_sensitive.to_lowercase().as_str() {
            "true" => true,
            "t" => true,
            "yes" => true,
            "y" => true,
            "1" => true,
            "false" => false,
            "f" => false,
            "no" => false,
            "n" => false,
            "0" => false,
            _ => {
                eprintln!("* The value of CASE_SENSITIVE doesn't match expected pattern!");
                return;
            }
        }
    } else {
        true
    };

        Ok(include) => include.split(',').map(|x| x.to_string()).collect(),

        Ok(include) => {
            if is_case_sensitive {
                include.split(',').map(|x| x.to_string()).collect()
            } else {
                include
                    .split(',')
                    .map(|x| x.to_string().to_lowercase())
                    .collect()
            }
        }

        Ok(exclude) => exclude.split(',').map(|x| x.to_string()).collect(),

        Ok(exclude) => {
            if is_case_sensitive {
                exclude.split(',').map(|x| x.to_string()).collect()
            } else {
                exclude
                    .split(',')
                    .map(|x| x.to_string().to_lowercase())
                    .collect()
            }
        }

        is_case_sensitive,

    is_case_sensitive: bool,

        is_case_sensitive: bool,

            is_case_sensitive,

    let content = message.plain_content.unwrap_or(message.content);

    let content = if settings.is_case_sensitive {
        message.content
    } else {
        message.content.to_lowercase()
    };

CASE_SENSITIVE=大文字/小文字を区別する(true/false、デフォルト:true)