code: def _Pcn_crp(x, dsz, Nv, dimN=2, dimC=1):
      
  
      return normalise(bcrop(x, dsz, dimN), dimN + dimC)
docs: Projection onto dictionary update constraint set: support
      projection and normalisation. The result is cropped to the
      support of the largest filter in the dictionary.
  
      Parameters
      ----------
      x  : array_like
         Input array
      dsz : tuple
        Filter support size(s), specified using the same format as the
        `dsz` parameter of :func:`bcrop`
      Nv : tuple
        Sizes of problem spatial indices
      dimN : int, optional (default 2)
        Number of problem spatial indices
      dimC : int, optional (default 1)
        Number of problem channel indices
  
      Returns
      -------
      y : ndarray
        Projection of input onto constraint set