docs: def conjugate(self):
          """The element-wise conjugate matrix
  
          This is defined only if all the entries in the matrix have a defined
          conjugate (i.e., they have a `conjugate` method). This is *not* the
          case for a matrix of operators. In such a case, only an
          :meth:`elementwise` :func:`adjoint` would be applicable, but this is
          mathematically different from a complex conjugate.
  
          Raises:
              NoConjugateMatrix: if any entries have no `conjugate` method
          """
          try:
              return Matrix(np_conjugate(self.matrix))
          except AttributeError:
              raise NoConjugateMatrix(
                  "Matrix %s contains entries that have no defined "
                  "conjugate" % str(self))