COUNTRIES_DICT = {
    "CA": {
        "nl_code": "5001",
        "iso_code": "CA",
        "name": "Canada",
    },
    "FR": {
        "nl_code": "5002",
        "iso_code": "FR",
        "name": "Frankrijk",
    },
    ....
}

from PyPDF2 import PdfReader

countries = {}
empty_data = {"nl_code": "", "iso_code": "", "name": ""}
reader = PdfReader("Tabel 34 Landen (gesorteerd op code).pdf")

for page in reader.pages:
    current_data = empty_data.copy()
    for line in page.extract_text().splitlines():
        line = line.strip()

        if len(line) == 4 and line.isdigit():
            current_data["nl_code"] = line
            continue

        if current_data["nl_code"] and len(line) == 2:
            current_data["iso_code"] = line
            continue

        if current_data["nl_code"] and current_data["iso_code"]:
            iso_code = current_data["iso_code"]
            current_data["name"] = line
            countries[iso_code] = current_data
            current_data = empty_data.copy()
            continue

print(countries)
print(len(countries))