Return the deposit address for the given major currency.

        :param currency: Major currency name in lowercase (e.g. "btc", "eth").
        :type currency: str | unicode
        :return: Deposit address.
        :rtype: str | unicode

def get_deposit_address(self, currency):
        """Return the deposit address for the given major currency.

        :param currency: Major currency name in lowercase (e.g. "btc", "eth").
        :type currency: str | unicode
        :return: Deposit address.
        :rtype: str | unicode
        """
        self._validate_currency(currency)
        self._log('get deposit address for {}'.format(currency))
        coin_name = self.major_currencies[currency]
        return self._rest_client.post(
            endpoint='/{}_deposit_address'.format(coin_name)
        )