def METHOD_NAME(self,v):
    numberTypes = ['http://www.w3.org/2001/XMLSchema#float', 'http://www.w3.org/2001/XMLSchema#decimal',
                 'http://www.w3.org/2001/XMLSchema#double','http://www.w3.org/2001/XMLSchema#integer']
    if v.datatype  is 'http://www.w3.org/2001/XMLSchema#integer' or v.datatype is 'http://www.w3.org/2001/XMLSchema#decimal' or  v.datatype is 'http://www.w3.org/2001/XMLSchema#float' or  v.datatype is 'http://www.w3.org/2001/XMLSchema#double':
        return True
    elif isinstance(v.value, float) or isinstance(v.value, int):
        return True
    elif isinstance(v.value, str):
        try:
            d = float(v.value)
            return True
        except ValueError:
            return False