"include" option in rest api

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model

class Pod(models.Model):
    pod_serial = models.CharField(max_length=255)
    formula = models.ForeignKey(Formula, on_delete=models.CASCADE)
    batch_id = models.IntegerField(max_length=9)
    customer = models.ForeignKey(Customer, on_delete=models.SET_NULL, null=True)
    pod_version = models.FloatField(max_length=20)
    assembly_date = models.DateField(default=datetime.now)
    manufacture_date = models.DateField(default=datetime.now)
    used_at_date = models.DateField(default=datetime.now)
    discarded_date = models.DateField(default=datetime.now)
    status = models.IntegerField(max_length=9)

serializer

from xml.etree.ElementInclude import include
from rest_framework_json_api import serializers
from api.device_managements.models import Pod
from api.sales.serializers import FormulaSerializer


class PodSerializer(serializers.ModelSerializer):

    formula = FormulaSerializer()
    class Meta:
        model = Pod
        fields = ['pod_serial','pod_version','manufacture_date','formula','customer']

i need the formula field when i add the option in url only.
eg: http://127.0.0.1:8000/api/pods?***include=formula***

otherwise should return without the formula field. does anyone have the idea?