async def get_header_block_by_height(self, height: int, header_hash: bytes32, tx_filter: bool=True) -> Optional[HeaderBlock]:
    header_dict: Dict[(bytes32, HeaderBlock)] = (await self.get_header_blocks_in_range(height, height, tx_filter))
    if (len(header_dict) == 0):
        return None
    if (header_hash not in header_dict):
        return None
    return header_dict[header_hash]
async def get_header_block_by_height(self, height: int, header_hash: bytes32, tx_filter: bool=True) -> Optional[HeaderBlock]:
    header_dict: Dict[(bytes32, HeaderBlock)] = (await self.get_header_blocks_in_range(height, height, tx_filter))
    if (len(header_dict) == 0):
        return None
    if (header_hash not in header_dict):
        return None
    return header_dict[header_hash]