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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 tag_from_element(el):
 """ Convert an Element into a Tag. ``el`` is an instance of ``Element``. Returns an instance of the corresponding subclass of ``TagBase``. """

    tag = el.tag
    namespace = None
    if tag.startswith('{'):
        # Strip namespace of the form "{namespace}tag"
        namespace,tag = tag[1:].split('}')
    try:
        cls = globals()[tag.title()]
        if not issubclass(cls, TagBase):
            raise KeyError()
    except KeyError:
        raise ValueError("TagBase doesn't have a subclass for '%s'." % tag)
    children = [tag_from_element(c) for c in el]
    tag = cls(*children, **el.attrib)
    tag.text = el.text
    tag.tail = el.tail
    if namespace:
        tag.attrib['xmlns'] = namespace
    return tag