input: 
  def matrix_operations(matrix_class_code: str) -> str:
      """Given a string containing the definition of a matrix operations class in Python, extract the 
      class name and list all the operations that the class can perform.
      >>> matrix_operations("class Matrix: def __init__(self, m, n, lst): self.m = m ... def add(self, mat2): ...")
      "Matrix: ['__init__', 'add', 'sub', 'mul', 'transpose']"
      """
  
output:     import re
  
      class_name_match = re.search(r'class (\w+):', matrix_class_code)
      if not class_name_match:
          return ""
      
      class_name = class_name_match.group(1)
      method_matches = re.findall(r'def (\w+)\(', matrix_class_code)
      
      return f"{class_name}: {sorted(method_matches)}"