input: Write a python function to categorize programming languages based on their paradigms.
  assert categorize_languages({'C': 'Imperative', 'Python': 'Object-Oriented'}) == {'Imperative': ['C'], 'Object-Oriented': ['Python']}
  assert categorize_languages({'Go': 'Imperative/Functional', 'Ruby': 'Object-Oriented/Functional'}) == {'Imperative/Functional': ['Go'], 'Object-Oriented/Functional': ['Ruby']}
  assert categorize_languages({'Java': 'Object-Oriented', 'Scala': 'Object-Oriented'}) == {'Object-Oriented': ['Java', 'Scala']}
output: def categorize_languages(languages):
      categorized = {}
      for lang, paradigm in languages.items():
          if paradigm not in categorized:
              categorized[paradigm] = []
          categorized[paradigm].append(lang)
      return categorized