cython >= 0.29, < 3.0; python_version == "2.6"
cython >= 0.29, < 3.0; python_version == "2.7"
cython >= 0.26, < 0.27; python_version == "3.2"
cython >= 0.29, < 3.0; python_version == "3.3"
cython >= 0.29, < 3.0; python_version == "3.4"
cython >= 0.29, < 3.1; python_version >= "3.5"
