fix typo in docstring
fix typo in docstring

RexFuzzle/sfepy,lokik/sfepy,vlukes/sfepy,RexFuzzle/sfepy,vlukes/sfepy,lokik/sfepy,vlukes/sfepy,RexFuzzle/sfepy,RexFuzzle/sfepy,sfepy/sfepy,rc/sfepy,BubuLK/sfepy,lokik/sfepy,lokik/sfepy,rc/sfepy,BubuLK/sfepy,sfepy/sfepy,sfepy/sfepy,BubuLK/sfepy,rc/sfepy