old_contents: from django.forms import ModelForm
  from .models import Student, School, OneTime, SpecificDateTime
  from django import forms
  from django.utils.translation import ugettext as _
  
  
  class StudentForm(ModelForm):
      class Meta:
          model = Student
          fields = ['name', 'surname', 'country', 'birthDate', 'weight_kg', 'blood',
                    'height_cm', 'primary_school', 'secondary_school']
  
  
  class SchoolForm(ModelForm):
      class Meta:
          model = School
          fields = ['name', 'address', 'region', 'postcode', 'country', 'build_date']
  
  
  class OneTimeForm(ModelForm):
      class Meta:
          model = OneTime
          fields = ['start_datetime', 'stop_datetime', 'stop_type', 'lifetime_quantity', 'lifetime_unit']
  
  
  class SpecificDateTime(ModelForm):
  
      PERIOD_MIN = 0
      PERIOD_HOUR = 1
      PERIOD_DAY = 2
      PERIOD_MONTH = 3
      PERIOD_YEAR = 4
      PERIOD_FOREVER = 5
  
      LIFETIME_UNIT = (
          (PERIOD_MIN, _('minutes')),
          (PERIOD_HOUR, _('hours')),
          (PERIOD_DAY, _('days')),
          (PERIOD_MONTH, _('months')),
          (PERIOD_YEAR, _('Stop every year')),
          (PERIOD_FOREVER, _('NonStop')),
      )
  
      class Meta:
          model = SpecificDateTime
          fields = ['schedule_category', 'start_datetime', 'stop_datetime',
                    'lifetime_quantity', 'lifetime_unit', 'month_json', 'days_json']
  
      name = forms.MultipleChoiceField(widget=forms.CheckboxSelectMultiple,
                                       choices=LIFETIME_UNIT)
  
new_contents: from django.forms import ModelForm
  from .models import Student, School, OneTime, SpecificDateTime
  from django import forms
  from django.utils.translation import ugettext as _
  from django.contrib.postgres import forms as pgsql_forms
  
  class StudentForm(ModelForm):
      class Meta:
          model = Student
          fields = ['name', 'surname', 'country', 'birthDate', 'weight_kg', 'blood',
                    'height_cm', 'primary_school', 'secondary_school']
  
  
  class SchoolForm(ModelForm):
      class Meta:
          model = School
          fields = ['name', 'address', 'region', 'postcode', 'country', 'build_date']
  
  
  class OneTimeForm(ModelForm):
      class Meta:
          model = OneTime
          fields = ['start_datetime', 'stop_datetime', 'stop_type', 'lifetime_quantity', 'lifetime_unit']
  
  
  class SpecificDateTimeForm(ModelForm):
  
      PERIOD_MIN = 0
      PERIOD_HOUR = 1
      PERIOD_DAY = 2
      PERIOD_MONTH = 3
      PERIOD_YEAR = 4
      PERIOD_FOREVER = 5
  
      LIFETIME_UNIT = (
          (PERIOD_MIN, _('minutes')),
          (PERIOD_HOUR, _('hours')),
          (PERIOD_DAY, _('days')),
          (PERIOD_MONTH, _('months')),
          (PERIOD_YEAR, _('Stop every year')),
          (PERIOD_FOREVER, _('NonStop')),
      )
  
      class Meta:
          model = SpecificDateTime
          fields = ['start_datetime', 'stop_datetime',
                    'lifetime_quantity', 'lifetime_unit', 'month_json', 'days_json']
  
      name = forms.MultipleChoiceField(widget=forms.CheckboxSelectMultiple,
                                       choices=LIFETIME_UNIT)
  
      json = pgsql_forms.JSONField
  
subject: remove schedule_category