code: def repr_part(self):
          
          # Lazy import to improve `import odl` time
          import scipy.sparse
  
          if scipy.sparse.isspmatrix(self.matrix):
              optargs = [('matrix', str(self.matrix), '')]
          else:
              optargs = [('matrix', array_str(self.matrix, nprint=10), '')]
  
          optargs.append(('exponent', self.exponent, 2.0))
          return signature_string([], optargs, mod=[[], ['!s', ':.4']])
docs: Return a string usable in a space's ``__repr__`` method.