def support(node):
    """Get support value of a node.

    Parameters
    ----------
    node : skbio.TreeNode
        node to get support value of

    Returns
    -------
    float or None
        support value of the node, or None if not available

    Notes
    -----
    A "support value" is defined as the numeric form of a whole node label
    without ":", or the part preceding the first ":" in the node label.

    - For examples: "(a,b)1.0", "(a,b)1.0:2.5", and "(a,b)'1.0:species_A'". In
    these cases the support values are all 1.0.

    - For examples: "(a,b):1.0" and "(a,b)species_A". In these cases there are
    no support values.

    Examples
    --------
    >>> from skbio import TreeNode
    >>> tree = TreeNode.read(['((a,b)99,(c,d):1.0);'])
    >>> support(tree.lca(['a', 'b']))
    99.0
    >>> support(tree.lca(['c', 'd'])) is None
    True
    """
    try:
        return float(node.name.split(':')[0])
    except (ValueError, AttributeError):
        return None