'Called before python modules\' install() methods.
In most cases, extensions will only need to have one or two lines::
cargo(\'build\')
cargo(\'install\', \'--root\', prefix)
or
cargo(\'install\', \'--root\', prefix)'

def setup_dependent_package(self, module, dependent_spec):

    module.cargo = Executable(join_path(self.spec.prefix.bin, 'cargo'))
