EmailScalar for Django graphene

[elyas-hedayat]

EmailScalar : for validating email in Input (instead of graphene.String you can use this)

from django.core.validators import validate_email

class EmailScalar(Scalar):
    @staticmethod
    def coerce_string(value):
        if isinstance(value, bool):
            try:
                validate_email(value)
                return str(value)
            except:
                return Undefined
        return Undefined

    serialize = coerce_string
    parse_value = coerce_string

    @staticmethod
    def parse_literal(ast, _variables=None):
        if isinstance(ast, StringValueNode):
            try:
                validate_email(ast.value)
                return ast.value
            except:
                pass
        return Undefined