code: def test_repr():
      A = interface.LinearOperator(shape=(1, 1), matvec=lambda x: 1)
      repr_A = repr(A)
      assert_("unspecified dtype" not in repr_A, repr_A)
  
imports: from functools import partial
  from itertools import product
  import operator
  import pytest
  from pytest import raises, warns
  from numpy.testing import assert_, assert_equal
  import numpy
  import scipy.sparse
  from scipy.sparse.linalg import interface
  from scipy.sparse.sputils import matrix
label_desc: Use image node_id 1 for calling a global function with example usage: test_repr() without return types