Api.php
private function checkAuthorize(array $fields)
	{
		if ( false === $fields['merchant_id'] )
		{
			throw new ApiException(Errors::ERRCODE_MERCHANT_ID_INVALID);
		}
		if ( false === $fields['merchant_password'] )
		{
			throw new ApiException(Errors::ERRCODE_MERCHANT_PASSWORD_INVALID);
		}
		if ( false === $fields['receiver_email'] )
		{
			throw new ApiException(Errors::ERRCODE_MERCHANT_EMAIL_INVALID);
		}
	}
private function checkAuthorize(array $fields)
	{
		if ( false === $fields['merchant_id'] )
		{
			throw new ApiException(Errors::ERRCODE_MERCHANT_ID_INVALID);
		}
		if ( false === $fields['merchant_password'] )
		{
			throw new ApiException(Errors::ERRCODE_MERCHANT_PASSWORD_INVALID);
		}
		if ( false === $fields['receiver_email'] )
		{
			throw new ApiException(Errors::ERRCODE_MERCHANT_EMAIL_INVALID);
		}
	}
Check ahthorize
@internal: called by checkFields function

@param array $fields
@throw ApiException