code: def setup_method(self):
      x = np.arange(5, dtype="float")
      mx = MMatrix(x, mask=[0, 1, 0, 0, 0])
      self.data = (x, mx)
  
imports: import numpy
  from numpy.testing import assert_warns
  from numpy.ma.testutils import assert_, assert_equal, assert_raises, assert_array_equal
  from numpy.ma.core import masked_array, masked_values, masked, allequal, MaskType, getmask, MaskedArray, nomask, log, add, hypot, divide
  from numpy.ma.extras import mr_
  from numpy.compat import pickle
label_desc: Use image node_id 1 for calling the TestSubclassing obj's underlying member method code with example usage: obj.setup_method() without return types