in src/main/groovy/com/jetbrains/python/envs/PythonEnvsExtension.groovy [79:86]
void virtualenv(final String envName, final String sourceEnvName, final List<String> packages = null) {
Python pythonEnv = (pythons + pythonsFromZip).find { it.name == sourceEnvName }
if (pythonEnv != null) {
virtualEnvs << new VirtualEnv(envName, envsDirectory, pythonEnv, packages)
} else {
println("Specified environment '$sourceEnvName' for virtualenv '$envName' isn't found")
}
}