pybel reports it can output copyformat, but it seemingly cannot.
In [1]: import pybel
In [2]: pybel.outformats['copy']
Out[2]: 'Copy raw text'
In [3]: mol = pybel.readfile("sdf", "Components-pub_less_than_300MW.sdf.gz").next()
In [4]: mol.write('copy','test.sdf')
Not a valid output format