Add docstring frequency finder (#14833)

* corrected the typos

* added the docstrings in the functions

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update camel_case_to_snake_case.py

* Improve docstring clarity in frequency_finder.py

Updated docstrings for get_letter_count and get_item_at_index_zero functions for clarity.

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

strings/frequency_finder.py

@@ -36,6 +36,8 @@ LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 
 
 def get_letter_count(message: str) -> dict[str, int]:
+    """get_letter_count() takes message as a parameter, which should be a string.
+    It returns a dictionary where the string is a key and an integer is a value."""
     letter_count = dict.fromkeys(string.ascii_uppercase, 0)
     for letter in message.upper():
         if letter in LETTERS:
@@ -45,6 +47,7 @@ def get_letter_count(message: str) -> dict[str, int]:
 
 
 def get_item_at_index_zero(x: tuple) -> str:
+    """Take a tuple x as a parameter and return a string."""
     return x[0]