You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mmdb_reader.rs
    path of file: ./repos/sniffnet/src/mmdb/types
    
    the code of the file until where you have to start completion: use maxminddb::Reader;

pub enum MmdbReader {
    Default(Reader<&'static [u8]>),
    Custom(Reader<Vec<u8>>),
}

impl MmdbReader {
    pub fn from(mmdb_path: &Strin
    
    pub fn from(mmdb_path: &String, default_mmdb: &'static [u8]) -> MmdbReader {
        let default_reader = maxminddb::Reader::from_source(default_mmdb).unwrap();
        if mmdb_path.is_empty() {
            MmdbReader::Default(default_reader)
        } else {
            let custom_reader_result = maxminddb::Reader::open_readfile(mmdb_path);
            if let Ok(custom_reader) = custom_reader_result {
                return MmdbReader::Custom(custom_reader);
            }
            MmdbReader::Default(default_reader)
        }
    }