def strip_alias_prefix(alias):
    """
    Splits `alias` on ':' to strip off any alias prefix. Aliases have a lab-specific prefix with
    ':' delimiting the lab name and the rest of the alias; this delimiter shouldn't appear
    elsewhere in the alias.

    Args:
        alias: `str`. The alias.

    Returns:
        `str`: The alias without the lab prefix.

    Example::

          strip_alias_prefix("michael-snyder:B-167")
          # Returns "B-167"

    """
    return alias.split(":")[-1]