message: unwrap->ok? in jsonrepr.rs
diff: @@ -73,7 +73,7 @@ fn to_json<'a>(cl_type: &CLType, bytes: &'a [u8]) -> Option<(Value, &'a [u8])> {
  }
  }
  CLType::Map { key, value } => {
  - let (num_keys, mut stream) = u32::from_bytes(bytes).unwrap();
  + let (num_keys, mut stream) = u32::from_bytes(bytes).ok()?;
  let mut result: Vec<Value> = Vec::new();
  for _ in 0..num_keys {
  let (k, remainder) = to_json(key, stream)?;
  