fixing travis

examples/python_example_2d.py

@@ -0,0 +1,21 @@
+import histogram as hg
+import numpy as np
+
+h = hg.histogram(hg.axis.regular(10, -3, 3, uoflow=False),
+                 hg.axis.regular(10, -3, 3, uoflow=False))
+xy = np.random.randn(2000).reshape((1000, 2))
+xy[:,1] *= 0.5
+h.fill(xy)
+
+x = np.array(h.axis(0)) # axis instances behave like sequences
+y = np.array(h.axis(1))
+z = np.asarray(h)       # creates a view (no copy involved)
+
+try:
+    import matplotlib.pyplot as plt
+    plt.pcolor(x, y, z.T)
+    plt.xlabel("x")
+    plt.ylabel("y")
+    plt.savefig("example_2d_python.png")
+except ImportError:
+    pass