[Discuss-gnuradio] About a typeerror

Hi, everyone, When I ran a python program, I met such a question, can you holp me to point out where the problem is? The problem is as follows: Traceback (most recent call last):   File "MainFrame.py", line 106, in OnDBPSK_Demodulate     objDemod = DBPSKDemod.dbpsk_demod(fg)   File "/home/cwang/prj/ufl/source_code/Receiver/DBPSKDemod.py", line 153, in __init__     gr.hier_block2.__init__(self, self._fg, self.pre_scaler, self.unpack)    #changed from block to block2, cwang 9.29   File "/usr/local/lib/python2.6/dist-packages/gnuradio/gr/hier_block2.py", line 42, in __init__     self._hb = hier_block2_swig(name, input_signature, output_signature)   File "/usr/local/lib/python2.6/dist-packages/gnuradio/gr/gnuradio_swig_py_runtime.py", line 1015, in hier_block2_swig     return _gnuradio_swig_py_runtime.hier_block2_swig(*args, **kwargs) TypeError: in method 'hier_block2_swig', argument 1 of type 'std::string const' Thanks. Cheng