Get code selected by user.

        Returns:
            str: Code or None in case that user didn't selected anything yet.

def get(cls):
        """
        Get code selected by user.

        Returns:
            str: Code or None in case that user didn't selected anything yet.
        """
        if cls.is_twoconspect:
            return cls.subconspect_el.value or None

        input_value = cls.input_el.value.strip()

        # blank user input -> no value was yet set
        if not input_value:
            return None

        mdt = conspectus.mdt_by_name.get(input_value)

        if not mdt:
            alert("Invalid sub-conspect `%s`!" % input_value)
            return None

        return mdt