impl EntryWithHeader {
    pub fn new(entry: Entry, header: ChainHeader) -> EntryWithHeader {
        EntryWithHeader { entry, header }
    }
}

pub struct ChainFoo(ChainHeader, Entry);

impl ChainFoo {

  pub fn new(header: ChainHeader, entry: Entry) -> Result<ChainFoo, HolochainError> {
    if header.entry().address() = entry.address() {
      Ok(ChainFoo(header, entry))
    }
    else {
      Err(HolochainError::InternalError("Header/Entry mismatch"))
    }
  }

  pub fn header(&self) -> ChainHeader {
    self.0.clone()
  }

  pub fn entry(&self) -> Entry {
    self.1.clone()
  }

}