'Read a word, it returns None if ad is not an address.
The parameter section is the section where ad is. It\'s just use for
optimization and used to not recall get_section.'

def read_word(self, ad, section=None):

    if (section is None):
        section = self.__binary.get_section(ad)
        if (section is None):
            return None
    return section.read_word(ad)
