pub fn best_block(&self, hash_or_height: HashOrHeight) -> Option<Arc<Block>> {
        self.mem
            .best_block(hash_or_height)
            .map(|contextual| contextual.block)
            .or_else(|| self.disk.block(hash_or_height))
    }
/// Return the block identified by either its `height` or `hash` if it exists
/// in the current best chain.
Return the block identified by either its `height` or `hash` if it exists
in the current best chain.
Return the block identified by either its ` height ` or ` hash ` if it exists in the current best chain .
pub fn best_block(&self, hash_or_height: HashOrHeight) -> Option<Arc<Block>> {
        self.mem
            .best_block(hash_or_height)
            .map(|contextual| contextual.block)
            .or_else(|| self.disk.block(hash_or_height))
    }
pub fn best_block ( & self , hash_or_height : HashOrHeight ) -> Option < Arc < Block > > { self . mem . best_block ( hash_or_height ) . map ( | contextual | contextual . block ) . or_else ( | | self . disk . block ( hash_or_height ) ) }
Return the block identified by either its `height` or `hash` if it exists
in the current best chain.
Return the block identified by either its ` height ` or ` hash ` if it exists in the current best chain .
&self
hash_or_height
HashOrHeight