require group parameter

pytube/cipher.py

@@ -16,6 +16,7 @@ signature and decoding it.
 
 import re
 from itertools import chain
+from typing import List
 
 from pytube.exceptions import RegexMatchError
 from pytube.helpers import regex_search, create_logger
@@ -58,7 +59,7 @@ def get_initial_function_name(js: str) -> str:
     raise RegexMatchError("get_initial_function_name not found")
 
 
-def get_transform_plan(js: str) -> str:
+def get_transform_plan(js: str) -> List[str]:
     """Extract the "transform plan".
 
     The "transform plan" is the functions that the ciphered signature is

pytube/helpers.py

@@ -12,9 +12,7 @@ from pytube.exceptions import RegexMatchError
 logger = logging.getLogger(__name__)
 
 
-def regex_search(
-    pattern: str, string: str, group: Optional[int] = None,
-):
+def regex_search(pattern: str, string: str, group: int) -> str:
     """Shortcut method to search a string for a given pattern.
 
     :param str pattern:
@@ -34,17 +32,13 @@ def regex_search(
         raise RegexMatchError(
             "regex pattern ({pattern}) had zero matches".format(pattern=pattern),
         )
-    else:
-        logger.debug(
-            "finished regex search: %s",
-            pprint.pformat(
-                {"pattern": pattern, "results": results.group(0),}, indent=2,
-            ),
-        )
-        if group is not None:
-            return results.group(group)
-        else:
-            return results
+
+    logger.debug(
+        "finished regex search: %s",
+        pprint.pformat({"pattern": pattern, "results": results.group(0),}, indent=2,),
+    )
+
+    return results.group(group)
 
 
 def apply_mixin(dct, key, func, *args, **kwargs):

tests/test_helpers.py

@@ -7,12 +7,11 @@ from pytube.exceptions import RegexMatchError
 
 def test_regex_search_no_match():
     with pytest.raises(RegexMatchError):
-        helpers.regex_search("^a$", "")
+        helpers.regex_search("^a$", "", group=0)
 
 
 def test_regex_search():
-    # TODO(nficano): should check isinstance
-    assert helpers.regex_search("^a$", "a") is not None
+    assert helpers.regex_search("^a$", "a", group=0) == "a"
 
 
 def test_safe_filename():