def future_import(feature, node):
    root = find_root(node)

    if does_tree_import(u"__future__", feature, node):
        return

    # Look for a shebang or encoding line
    shebang_encoding_idx = None

    for idx, node in enumerate(root.children):
        # Is it a shebang or encoding line?
        if is_shebang_comment(node) or is_encoding_comment(node):
            shebang_encoding_idx = idx
        if node.type == syms.simple_stmt and \
           len(node.children) > 0 and node.children[0].type == token.STRING:
            # skip over docstring
            continue
        names = check_future_import(node)
        if not names:
            # not a future statement; need to insert before this
            break
        if feature in names:
            # already imported
            return

    import_ = FromImport(u'__future__', [Leaf(token.NAME, feature, prefix=" ")])
    if shebang_encoding_idx == 0 and idx == 0:
        # If this __future__ import would go on the first line,
        # detach the shebang / encoding prefix from the current first line.
        # and attach it to our new __future__ import node.
        import_.prefix = root.children[0].prefix
        root.children[0].prefix = u''
        # End the __future__ import line with a newline and add a blank line
        # afterwards:
    children = [import_ , Newline()]
    root.insert_child(idx, Node(syms.simple_stmt, children))
Exponential Linear Unit function.
dataset/ETHPy150Open PythonCharmers/python-future/src/libfuturize/fixer_util.py/future_import--crossover with--dataset/ETHPy150Open pfnet/chainer/chainer/functions/activation/elu.py/elu