<?xml version="1.0"?>
<tool_dependency>
    <package name="khmer" version="2.0">
        <install version="1.0">
            <actions>
                <action type="setup_python_environment">
                    <repository name="package_python_2_7" owner="iuc">
                        <package name="python" version="2.7" />
                    </repository>
                    <package md5sum="1f610abd021254e21b082179a100cd39">https://pypi.python.org/packages/source/k/khmer/khmer-2.0.tar.gz</package>
                </action>
            </actions>
        </install>
    </package>
</tool_dependency>

<?xml version="1.0"?>
<tool_dependency>
    <package name="python" version="2.7.10">
        <repository name="package_python_2_7_10" owner="iuc" prior_installation_required="True" />
    </package>
    <package name="khmer" version="2.0">
        <install version="1.0">
            <actions>
                <action type="setup_python_environment">
                    <repository name="package_python_2_7_10" owner="iuc">
                        <package name="python" version="2.7.10" />
                    </repository>
                    <package md5sum="27d6f711ae0db6cfd1eb37f95621dfb5">https://pypi.python.org/packages/source/b/bz2file/bz2file-0.98.tar.gz</package>
                    <package md5sum="611dd11105489e4153265e055f13debd">https://pypi.python.org/packages/source/s/screed/screed-0.9.tar.gz</package>
                    <package md5sum="1f610abd021254e21b082179a100cd39">https://pypi.python.org/packages/source/k/khmer/khmer-2.0.tar.gz</package>
                </action>
            </actions>
        </install>
    </package>
</tool_dependency>

Add python-2.7.10 dependency to package_khmer_2_0
Add python-2.7.10 dependency to package_khmer_2_0
