In [151]: a = np.asarray(["a", "b"])

In [152]: a
Out[152]: 
array(['a', 'b'], 
      dtype='|S1')

In [153]: np.array_equal(a, a)
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-153-8f762db9db16> in <module>()
----> 1 np.array_equal(a, a)

/home/njs/.user-python2.7-64bit/lib/python2.7/site-packages/numpy/core/numeric.pyc in array_equal(a1, a2)
   1975     if a1.shape != a2.shape:
   1976         return False
-> 1977     return bool(logical_and.reduce(equal(a1,a2).ravel()))
   1978 
   1979 def array_equiv(a1, a2):

AttributeError: 'NotImplementedType' object has no attribute 'ravel'