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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def check_c_extensions(self, name=None):
 """ If C extensions cannot be run, emit a warning and return ``False``. Otherwise return ``True``. If ``name`` is not ``None``, check just the C extension with that name. :param name: the name of the Python C extension to test :type name: string :rtype: bool """

        if not gf.can_run_c_extension(name=name):
            if name is None:
                self.print_warning(u"Unable to load Python C Extensions")
            else:
                self.print_warning(u"Unable to load Python C Extension %s" % (name))
            self.print_warning(u"Running the slower pure Python code")
            self.print_warning(u"See the documentation for directions to compile the Python C Extensions")
            return False
        return True