anchor.diff:  
   -type sql_query() :: iodata().
   -type host() :: inet:ip_address() | inet:hostname().
  +-type password() :: string() | iodata() | fun( () -> iodata() ).
   -type connection() :: pid().
   -type connect_option() ::
       {host, host()}                                 |
       {username, string()}                           |
  -    {password, string()}                           |
  +    {password, password()}                         |
       {database, DBName     :: string()}             |
       {port,     PortNum    :: inet:port_number()}   |
       {ssl,      IsEnabled  :: boolean() | required} |
  
positive.code: connect(Host, Username, Opts) ->
      connect(Host, Username, "", Opts).
  
  -spec connect(host(), string(), string(), connect_opts())
          -> {ok, Connection :: connection()} | {error, Reason :: connect_error()}.
  %% @doc connects to Postgres
  %% where
  
negative.code:         [connect_option()]
        | #{host => host(),
            username => string(),
            password => password(),
            database => string(),
            port => inet:port_number(),
            ssl => boolean() | required,
  