'Instantiate with the latex representing the math.
Optionally include parenthesis to wrap around it and the height.
`parens` must be one of \'(\', \'[\' or \'{\'.
`tall` is a boolean (see note above).'

def __init__(self, latex, parens=None, tall=False):

    self.latex = latex
    self.sans_parens = latex
    self.tall = tall
    if (parens is not None):
        left_parens = parens
        if (left_parens == '{'):
            left_parens = '\\{'
        pairs = {'(': ')', '[': ']', '\\{': '\\}'}
        if (left_parens not in pairs):
            raise Exception(u"Unknown    parenthesis    '{}':    coder    error".format(left_parens))
        right_parens = pairs[left_parens]
        if self.tall:
            left_parens = ('\\left' + left_parens)
            right_parens = ('\\right' + right_parens)
        self.latex = u'{left}{expr}{right}'.format(left=left_parens, expr=latex, right=right_parens)
