Validate csv file in Django

Question

I am trying to insert a function to validate the upload of a . csv, but when placing it the following error was presented:

ImportError: cannot import name 'PresencaProf' from partially initialized module 'parte1.models' (most likely due to a circular import)

I researched, but no solution was useful to me. I don’t know what this mistake is about, I just got a sense when I saw it running sequentially, but it didn’t fit, because as far as I could tell, everything was right.

Filing cabinet forms.py:

from django.forms import forms
from django import forms
from parte1.models import PresencaProf, PresencaAula


class UploadArquivo(forms.ModelForm):


    class Meta:
        model = PresencaProf
        fields = ('evento', 'data', 'upload_csv',)


        def __init__(self, *args, **kwargs):
            super(UploadArquivo, self).__init__(*args, **kwargs)
            for visible in self.visible_fields():
                visible.field.widget.attrs['class'] = 'form-control'

        # Funcao para validar extensao csv
        def valida_csv_extensao(value):
            if not value.fk_evento__nome_evento.endswith('.csv'):
                raise forms.ValidationError("Erro!\nApenas arquivos .csv !")

        def clean(self):
            data = super(UploadArquivo, self).clean()

All help is welcome!!!

Filing cabinet models.py:

from django.core.validators import FileExtensionValidator
from django.db import models
from chamadas import forms


class PresencaProf(models.Model):

    data = models.DateField()
    evento = models.ForeignKey(Eventos, on_delete=models.RESTRICT)
    # validators=[FileExtensionValidator(['csv'] -> valida um csv
    upload_csv = models.FileField(upload_to = 'csv', blank=True, null=True)


    class Meta:
        verbose_name = "Regristo de presença"
        verbose_name_plural = "Registros de presenças"


class PresencaAula(models.Model):

    # atributo que pega o ID de um evento, relacionamento 1:N
    fk_evento = models.ForeignKey(Eventos, on_delete=models.RESTRICT, null=True, blank=True)
    fk_professor = models.ForeignKey(Professor, on_delete=models.RESTRICT, null=True, blank=True)
    data_aula = models.DateField()

    class Meta:

        verbose_name = "Presença por aula"
        verbose_name_plural = "Presenças por aulas"

Answer 1

in the imports of its py.models

from django.core.validators import FileExtensionValidator
from django.db import models
from chamadas import forms

removes the last line:

from django.core.validators import FileExtensionValidator
from django.db import models

These circular references are usually caused by imports, so always give a check...