def unindent_tree(element):
    """
    Removes the outermost indent. For example, the tree
    "<div>A<blockqote>B<div>C<blockquote>D</blockquote>E</div>F</blockquote>G</div>"
    is transformed to
    "<div>A<div>B<div>C<blockquote>D</blockquote>E</div>F</div>G</div>"
    """
    for el in element.iter():
        if is_indentation_element(el):
            el.attrib.clear()
            el.tag = 'div'
            return
Removes the outermost indent. For example, the tree
    "<div>A<blockqote>B<div>C<blockquote>D</blockquote>E</div>F</blockquote>G</div>"
    is transformed to
    "<div>A<div>B<div>C<blockquote>D</blockquote>E</div>F</div>G</div>"