How do filters work in wtforms?

Question

I read http://pythonhosted.org/WTForms/ , but nowhere does it define an interface for the filter function, as in the filter = keyword argument. Constructor Field (). Elsewhere, the .filter attribute is a list of calls made. So what is the calling sequence? Is one argument required and return the filtered value? Should this throw some kind of exception, if the argument is invalid, and if so, what exception (s)?

Answer 1

Basically,

class MyForm(Form):
    myfield = wtf.TextField('My field', filters=[lambda x: x])

filter - ( ) , . .

, , , : .