src/Model/Account.php
public function getCustomAssetBalanceValue(Asset $asset)
    {
        foreach ($this->getBalances() as $balance) {
            if ($balance->getAssetCode() !== $asset->getAssetCode()) continue;
            if ($balance->getAssetIssuerAccountId() != $asset->getIssuer()->getAccountIdString()) continue;

            return $balance->getBalance();
        }

        return null;
    }
public function getCustomAssetBalanceValue(Asset $asset)
    {
        foreach ($this->getBalances() as $balance) {
            if ($balance->getAssetCode() !== $asset->getAssetCode()) continue;
            if ($balance->getAssetIssuerAccountId() != $asset->getIssuer()->getAccountIdString()) continue;

            return $balance->getBalance();
        }

        return null;
    }
Returns the numeric balance of the given asset

@param Asset $asset
@return null|string