from operator import mul


def is_mul(var):
    """
    Match a variable with `x * y * z * ...`.

    Parameters
    ----------
    var
        The Variable to analyze.

    Returns
    -------
    object
        A list [x, y, z, ...] if `var` is of the form `x * y * z * ...`,
        or None if `var` cannot be cast into this form.

    """
    if var.owner and var.owner.op == mul:
        return var.owner.inputs
    else:
        return None