code: def process(self, form, post):
          if not isinstance(form, FormMeta):
              raise TypeError('Given form is not a valid WTForm.')
          re_field_name = re.compile(r'\%([a-zA-Z0-9_]*)\%')
          class F(form):
              pass
          for field, data in post.iteritems():
              if field in F():
                  continue
              else:
                  if field in self._dyn_fields:
                      field_cname = field
                      current_set_number = None
                  elif (field.split('_')[-1].isdigit()
                        and field[:-(len(field.split('_')[-1]))-1] in self._dyn_fields.keys()):
                      field_cname = field[:-(len(field.split('_')[-1]))-1]
                      current_set_number = str(field.split('_')[-1])
                  else:
                      continue
              validators = []
              if 'validators' in self._dyn_fields[field_cname]:
                  for validator in self._dyn_fields[field_cname]['validators']:
                      args = []
                      kwargs = {}
                      if 'args' in self._dyn_fields[field_cname]\
                         [validator.__name__]:
                          if not current_set_number:
                              args = self._dyn_fields[field_cname]\
                                     [validator.__name__]['args']
                          else:
                              for arg in self._dyn_fields[field_cname]\
                                  [validator.__name__]['args']:
                                  try:
                                      arg = re_field_name.sub(r'\1'+'_'+current_set_number,
                                                              arg)
                                  except:
                                      pass
                                  args.append(arg)
                      if 'kwargs' in self._dyn_fields[field_cname]\
                         [validator.__name__]:
                          if not current_set_number:
                              kwargs = self._dyn_fields[field_cname]\
                                       [validator.__name__]['kwargs']
                          else:
                              for key, arg in self.iteritems(self._dyn_fields[field_cname]\
                                  [validator.__name__]['kwargs']):
                                  try:
                                      arg = re_field_name.sub(r'\1'+'_'+current_set_number,
                                                              arg)
                                  except:
                                      pass
                                  kwargs[key] = arg
                      validators.append(validator(*args, **kwargs))
              field_type = self._dyn_fields[field_cname]['type']
              field_label = self._dyn_fields[field_cname]['label']
              field_args = self._dyn_fields[field_cname]['args']
              field_kwargs = self._dyn_fields[field_cname]['kwargs']
              setattr(F, field, field_type(field_label,
                                           validators=validators,
                                           *field_args,
                                           **field_kwargs))
          if self.flask_wtf:
              form = F()
          else:
              form = F(post)
          return form