adding validation function for a survey to fix #51
adding validation function for a survey to fix #51

vsoch/expfactory-python,psiturk/psiturk-python,tangi75/expfactory-python,tangi75/expfactory-python,expfactory/expfactory-python,psiturk/psiturk-python,vsoch/expfactory-python,vsoch/expfactory-python,expfactory/expfactory-python,tangi75/expfactory-python,expfactory/expfactory-python,expfactory/expfactory-python,psiturk/psiturk-python,vsoch/expfactory-python,vsoch/expfactory-python,tangi75/expfactory-python,psiturk/psiturk-python,expfactory/expfactory-python,tangi75/expfactory-python