+ >>> print(vec(A))
+ [ 1]
+ [ 2]
+ [ 3]
+ [ 4]
+ <BLANKLINE>
+
+ Note that if ``real_matrix`` is a vector, this function is a no-op:
+
+ >>> v = matrix([1,2,3,4], (4,1))
+ >>> print(v)
+ [ 1]
+ [ 2]
+ [ 3]
+ [ 4]
+ <BLANKLINE>
+ >>> print(vec(v))
+ [ 1]
+ [ 2]
+ [ 3]
+ [ 4]
+ <BLANKLINE>