Install pyaml into virtual env

python/setup.py

@@ -42,7 +42,7 @@ setup(name='dune.codegen',
                 'dune.codegen.ufl',
                 'dune.codegen.ufl.transformations',
                 ],
-      install_requires=['sympy', 'frozendict', 'pytest', 'pytest-pep8', 'filelock', 'cerberus', 'pyyaml'],
+      install_requires=['sympy', 'frozendict', 'pytest', 'pytest-pep8', 'filelock', 'cerberus', 'pyaml'],
       cmdclass={'test': PyTest},
       entry_points = {
         "console_scripts": [