Return specfied GoSubDag initialization object.

def _get_edgesobj(gosubdag, **kws):
    """Return specfied GoSubDag initialization object."""
    # Keyword args (kws):
    #     1. dst_srcs_list  Used for edges pruned such that only GO terms
    #                       are retained which are between the sets of dst & srcs.
    #     2  traverse_parent & traverse_child
    #                       Used to generate a GoSubDag with all parent terms and/or
    #                       all child terms, without pruning any paths.
    # Call function, get_edgesobj, with:
    #     get_edgesobj(go2obj, dst_srcs_list=...)
    # Or any of:
    #     get_edgesobj(go2obj, go_sources=...)
    #     get_edgesobj(go2obj, go_sources=..., traverse_parent=...,)
    #     get_edgesobj(go2obj, go_sources=..., traverse_child=...,)
    #     get_edgesobj(go2obj, go_sources=..., traverse_parent=..., traverse_child=...,)
    dst_srcs_list = kws.get('dst_srcs_list', None)
    if dst_srcs_list is not None:
        return EdgesPath(gosubdag, dst_srcs_list)
    return EdgesRelatives(gosubdag,
                          kws.get('traverse_parent', True),
                          kws.get('traverse_child', False))