Fix coupon value check to allow fractions.
Fix coupon value check to allow fractions.

barrachri/epcon,matrixise/epcon,malemburg/epcon,malemburg/epcon,barrachri/epcon,artcz/epcon,PythonSanSebastian/epcon,artcz/epcon,artcz/epcon,matrixise/epcon,PythonSanSebastian/epcon,matrixise/epcon,malemburg/epcon,EuroPython/epcon,PythonSanSebastian/epcon,matrixise/epcon,malemburg/epcon,malemburg/epcon,artcz/epcon,PythonSanSebastian/epcon,PythonSanSebastian/epcon,artcz/epcon,matrixise/epcon,artcz/epcon,malemburg/epcon,barrachri/epcon,EuroPython/epcon,EuroPython/epcon,barrachri/epcon,barrachri/epcon,matrixise/epcon,PythonSanSebastian/epcon,EuroPython/epcon,barrachri/epcon