title: def __init__(self, *args, **kwargs): raise AttributeError("No constructor defined") AttributeError: No constructor defined
body: <p>I am trying to create a new DSP block in gnuradio using gr_modtool.py. gnuradio version is 3.3.0.
  I have following code in abc.h file in include folder</p>
  
  <pre><code> ifndef INCLUDED_ENERGYDETECTOR_LOCAL_SENSING_FF_H
   #define INCLUDED_ENERGYDETECTOR_LOCAL_SENSING_FF_H
   #include &lt;gr_block.h&gt;
  
   namespace gr {
     namespace energydetector {
   class ENERGYDETECTOR_API local_sensing_ff : virtual public gr_block
   {
    private:
  
    public:
      typedef boost::shared_ptr&lt;local_sensing_ff&gt; sptr;
      float d_pfa; int d_L; int d_samples;    
      static sptr make(float pfa=0.01,int L=16,int samples=1000);
      virtual void set_pfa(float input_a) { d_pfa = input_a; }  
      virtual int get_pfa() { return d_pfa; } 
      virtual void set_L(int input_b) { d_L = input_b; }  
      virtual int get_L() { return d_L; } 
      virtual void set_samples(int input_c) { d_samples = input_c; }  
     virtual int get_samples() { return d_samples; } 
       };
      } // namespace energydetector
    } // namespace gr
    #endif /* INCLUDED_ENERGYDETECTOR_LOCAL_SENSING_FF_H */
  </code></pre>
  
  <p>Implementation class for above header file is as:<br/></p>
  
  <pre><code> #ifndef INCLUDED_ENERGY-DETECTOR_LOCAL_SENSING_FF_IMPL_H
   #define INCLUDED_ENERGY-DETECTOR_LOCAL_SENSING_FF_IMPL_H
  
   #include &lt;energy-detector/local_sensing_ff.h&gt;
  
   namespace gr {
    namespace energydetector {
     class local_sensing_ff_impl : public local_sensing_ff
     {
     private:
        float d_pfa; int d_L; int d_samples;  
    public:
      local_sensing_ff_impl(float pfa,int L,int samples);
      ~local_sensing_ff_impl();
      void set_pfa(float input_a) { d_pfa = input_a; }  
      int get_pfa() { return d_pfa; } 
      void set_L(int input_b) { d_L = input_b; }  
      int get_L() { return d_L; } 
      void set_samples(int input_c) { d_samples = input_c; } 
      int get_samples() { return d_samples; }
          int general_work(int noutput_items,
             gr_vector_int &amp;ninput_items,
             gr_vector_const_void_star &amp;input_items,
             gr_vector_void_star &amp;output_items);
     };
    } // namespace energy-detector
   } // namespace gr
  #endif /* INCLUDED_ENERGY-DETECTOR_LOCAL_SENSING_FF_IMPL_H */
  </code></pre>
  
  <p>And SWIG file is abc.i as</p>
  
  <pre><code> #define ENERGY_DETECTOR_API
   %include "gnuradio.i"          // the common stuff
   %include "energydetector_swig_doc.i"
   %{
      #include "energydetector/local_sensing_ff.h"
    %}
  
    %include "energydetector/local_sensing_ff.h"
    GR_SWIG_BLOCK_MAGIC2(energydetector, local_sensing_ff);
  </code></pre>
  
  <p>It build successfully but while executing I get following error : <br/></p>
  
  <pre><code>def __init__(self, *args, **kwargs): raise AttributeError("No constructor defined")
  AttributeError: No constructor defined
  </code></pre>
  
  <p>Please help me out to debug this.</p>