def sitetree_breadcrumbs(parser, token):
    """Parses sitetree_breadcrumbs tag parameters.

    Two notation types are possible:
        1. Two arguments:
           {% sitetree_breadcrumbs from "mytree" %}
           Used to render breadcrumb path for "mytree" site tree.

        2. Four arguments:
           {% sitetree_breadcrumbs from "mytree" template "sitetree/mycrumb.html" %}
           Used to render breadcrumb path for "mytree" site tree using specific
           template "sitetree/mycrumb.html"

    """
    tokens = token.split_contents()
    use_template = detect_clause(parser, 'template', tokens)
    tokens_num = len(tokens)

    if tokens_num == 3:
        tree_alias = parser.compile_filter(tokens[2])
        return sitetree_breadcrumbsNode(tree_alias, use_template)
    else:
        raise template.TemplateSyntaxError(
            '%r tag requires two arguments. E.g. {%% sitetree_breadcrumbs from "mytree" %%}.' % tokens[0])