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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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