code: def test_phone_prefix_normalization():
      df = pd.DataFrame(
          data={
              "phone_num": [
                  "(123) 321-987-1",
                  "01 02 03 04 05",
                  "223-45-678",
                  "+86 10 6764 5489",
                  "89262134598",
                  "123",
                  "abc",
              ],
              "country": [
                  "US",
                  "EG",
                  "DZ",
                  "CN",
                  "RU",
                  "GB",
                  "Unknown",
              ],
              "something_else": ["a", "b", "c", "d", "e", "f", "g"],
          }
      )
      normalizer = PhoneNormalizer(df, "phone_num", "country")
      df["phone_num"] = normalizer.normalize()
  
      expected_df = pd.DataFrame(
          data={
              "phone_num": [
                  11233219871,
                  20102030405,
                  21322345678,
                  861067645489,
                  89262134598,
                  None,
                  None,
              ],
              "country": [
                  "US",
                  "EG",
                  "DZ",
                  "CN",
                  "RU",
                  "GB",
                  "Unknown",
              ],
              "something_else": ["a", "b", "c", "d", "e", "f", "g"],
          }
      )
      expected_df["phone_num"] = expected_df["phone_num"].astype(
          "Int64"
      )
  
      assert_frame_equal(df, expected_df)
  
file_path: upgini/tests/normalizer/phone_normalizer_test.py
imports: import pandas
  from pandas.testing import assert_frame_equal
  from upgini.normalizer.phone_normalizer import PhoneNormalizer
label_desc: Use image node_id 4 for calling a global function with example usage: test_phone_prefix_normalization() without return types