Shopify API: Most efficient way to bulk edit customer tags?

Question

I'm trying to do a makeshift system which updates the tags of customers using the API.

I have a dataframe with 2 fields - email and tag to be applied:

+----------------------+-----------+
| **email**            | **tag**   |
+----------------------+-----------+
| [email protected]    | active    |
+----------------------+-----------+
| [email protected]    | cancelled |
+----------------------+-----------+
| [email protected]    | example   |
+----------------------+-----------+
| [email protected] | some tag  |
+----------------------+-----------+

I use the following code to iterate through customers and update their tags:

for i in df.index:
    customer_string=str(shopify.Customer.search(query=df['email'][i])) #find id based on email    
    if customer_string!='[]':
        customer_id=customer_string[10:23]
        customer=shopify.Customer.find(customer_id)
        customer.tags=str(df['tag'][i])
        customer.save()

Would there be a more efficient way to update these tags, if it's intended to be done on regular basis?