Checks if a module is imported within the current namespace.

def module_is_imported(modname, scope=None):
    """Checks if a module is imported within the current namespace."""
    # return early if modname is not even cached
    if not module_is_in_cache(modname):
        return False

    if scope is None:  # use globals() of the caller by default
        scope = inspect.stack()[1][0].f_globals

    for m in scope.values():
        if isinstance(m, type(sys)) and m.__name__ == modname:
            return True

    return False