Using Biopython (Bio.Entrez) to fetch sequences from NCBI

fetch_sequences.py

from Bio import Entrez
Entrez.email = None  # change this!

assert Entrez.email is not None

# Read ids from file to a list
id_list = [ ... ]

results = {}
handle = Entrez.efetch(db="protein", id=id_list, retmode="xml")
with handle:
    records = Entrez.read(handle)
    for id_i, rec in zip(id_list, records):
        seq = rec['GBSeq_sequence'].upper()
        results[id_i] = seq