title: why error_messages doesn't working in Meta class?
body: <p><strong>My forms.py</strong></p>
  <pre><code>from django.core.exceptions import ValidationError
  from django.forms import ModelForm
  from django import forms
  from . models import Detail
  
  class DetailForm(ModelForm):
  name = forms.CharField(validators=[not_contain_number], required=True)
  email = forms.EmailField(required=True)
  phone_no = forms.IntegerField(
      validators=[number_validation], required=True)
  class Meta:
      model = Detail
      error_messages = {
          'name': {
              'required': 'enter your name',
          },
      }
      labels = {'name': 'Your Name', 'email': 'Your Email',
                'phone_no': 'Your Phone No.'}
      widgets = {'name': forms.TextInput(
          attrs={'placeholder': 'type your Name'})}
      fields = ['name', 'email', 'phone_no']
  </code></pre>
  <p><strong>Does it occurs due to my any mistake in ModelForm API?</strong></p>
  <blockquote>
  <p>It is working when i used it while defining:</p>
  </blockquote>
  <pre><code>class DetailForm(ModelForm):
          name = forms.CharField(validators=[not_contain_number], required=True,error_messages={'required': 'Enter Your Name'})
  </code></pre>