Function option_epoch_from_block_number 

pub fn option_epoch_from_block_number(
    with_epoch: bool,
    block_number: u64,
    epoch_height: u64,
) -> Option<EpochNumber>

Returns an Option<Epoch> based on a boolean condition of whether or not epochs are enabled, a block number, and the epoch height. If epochs are disabled or the epoch height is zero, returns None.