Remove pandas' formatters and converters

    Removes the custom converters added by :func:`register`. This
    attempts to set the state of the registry back to the state before
    pandas registered its own units. Converters for pandas' own types like
    Timestamp and Period are removed completely. Converters for types
    pandas overwrites, like ``datetime.datetime``, are restored to their
    original value.

    See Also
    --------
    deregister_matplotlib_converters

def deregister():
    """
    Remove pandas' formatters and converters

    Removes the custom converters added by :func:`register`. This
    attempts to set the state of the registry back to the state before
    pandas registered its own units. Converters for pandas' own types like
    Timestamp and Period are removed completely. Converters for types
    pandas overwrites, like ``datetime.datetime``, are restored to their
    original value.

    See Also
    --------
    deregister_matplotlib_converters
    """
    # Renamed in pandas.plotting.__init__
    for type_, cls in get_pairs():
        # We use type to catch our classes directly, no inheritance
        if type(units.registry.get(type_)) is cls:
            units.registry.pop(type_)

    # restore the old keys
    for unit, formatter in _mpl_units.items():
        if type(formatter) not in {DatetimeConverter, PeriodConverter,
                                   TimeConverter}:
            # make it idempotent by excluding ours.
            units.registry[unit] = formatter