def enable_ansi_color_substitution_globally():
    """
    Causes :py:func:`format_color` to replace color annotations with ansi
    esacpe sequences.

    It also affects :py:func:`ansi`.

    This is the case by default, so there is no need to call this everytime.

    If you have previously caused all substitutions to evaluate to an empty
    string by calling :py:func:`disable_ansi_color_substitution_globally`, then
    you can restore the escape sequences for substitutions by calling this
    function.
    """
    global _enabled
    _enabled = True
