def _unsolved_syms(eq, sort=False):
    'Returns the unsolved symbol present\n        in the equation `eq`.\n        '
    free = eq.free_symbols
    unsolved = ((free - set(known_symbols)) & set(all_symbols))
    if sort:
        unsolved = list(unsolved)
        unsolved.sort(key=default_sort_key)
    return unsolved
Returns the unsolved symbol present
in the equation `eq`.
def _unsolved_syms(eq, sort=False):
    'Returns the unsolved symbol present\n        in the equation `eq`.\n        '
    free = eq.free_symbols
    unsolved = ((free - set(known_symbols)) & set(all_symbols))
    if sort:
        unsolved = list(unsolved)
        unsolved.sort(key=default_sort_key)
    return unsolved