text: from django.db import models
  
  MARKER = "M"
  LINE = "L"
  POLYGON = "P"
  
  shapes = [
      (MARKER, "Marker"),
      (LINE, "Line"),
      (POLYGON, "Polygon")
  ]
  
  
  class Shape(models.Model):
  
      class Meta:
          db_table = "shape"
          app_label = "geometry"
  
      type = models.CharField(
          null=True,
          choices=shapes,
          max_length=1,
          blank=False,
          default=None
      )
  
      area = models.FloatField(blank=True, null=True)
      length = models.FloatField(blank=True, null=True)
  