'*default_font_prop*: A
:class:`~matplotlib.font_manager.FontProperties` object to use
for the default non-math font, or the base font for Unicode
(generic) font rendering.
*mathtext_backend*: A subclass of :class:`MathTextBackend`
used to delegate the actual rendering.'

def __init__(self, default_font_prop, mathtext_backend):

    self.default_font_prop = default_font_prop
    self.mathtext_backend = mathtext_backend
    self.used_characters = {}
