Django social auth validate user manually

I am using social auth of django with pipelines to get the email from social networks, but when I log in with facebook and then with google I am created two different accounts with the same mail

How can I avoid this by sending a message to the user, saying that there is already an account created with that mai, or directly logging in with the other account

This is my code from Social auth pipelines in settings.py

SOCIAL_AUTH_PIPELINE = (
    'social_core.pipeline.social_auth.social_details',
    'social_core.pipeline.social_auth.social_uid',
    'social_core.pipeline.social_auth.auth_allowed',
    'social_core.pipeline.social_auth.social_user',
    'social_core.pipeline.user.get_username',
    'social_core.pipeline.user.create_user',
    'users.utils.create_profile',              #<-- Crear UserProfile
    'social_core.pipeline.social_auth.associate_user',
    'social_core.pipeline.social_auth.load_extra_data',
    'social_core.pipeline.user.user_details',
    'users.utils.get_avatar'
)