Perform Frequency Counting and Analysis with collections.Counter

from collections import Counter

def analyze_word_frequency(text):
    """
    Analyzes word frequency in a given text string.
    Returns a Counter object and common words.
    """
    if not isinstance(text, str):
        raise TypeError("Input must be a string.")

    # Basic tokenization: convert to lowercase and split by non-alphanumeric
    # A more robust solution might use regex or NLTK
    words = [word.lower() for word in text.split() if word.isalpha()]
    
    word_counts = Counter(words)
    
    # Get the 3 most common words
    most_common = word_counts.most_common(3)
    
    return word_counts, most_common

def analyze_list_frequency(data_list):
    """
    Analyzes frequency of items in a list.
    """
    if not isinstance(data_list, list):
        raise TypeError("Input must be a list.")
        
    item_counts = Counter(data_list)
    return item_counts

# Example usage:
sample_text = "Python is great. Python is powerful. Python is versatile. Python Python Python."
word_freq, common_words = analyze_word_frequency(sample_text)
# print(f"Word Frequencies: {word_freq}")
# print(f"Most Common Words: {common_words}") # Expected: [('python', 6), ('is', 3), ('great', 1)]

sample_list = ['apple', 'banana', 'apple', 'orange', 'banana', 'apple', 'grape']
list_freq = analyze_list_frequency(sample_list)
# print(f"List Item Frequencies: {list_freq}") # Expected: Counter({'apple': 3, 'banana': 2, 'orange': 1, 'grape': 1})