input: Write a function to detect and fix Python syntax errors in a given code snippet. If the code snippet contains syntax errors, the function should attempt to fix them and return the corrected code. If the code snippet is already correct, return the original code. If the code snippet is empty, return an empty string.
  assert fix_python_syntax(def test ():
      x = 5
      y = 3 
      z)==def test():
      x = 5
      y = 3
      try:
          z
      except NameError:
          print("NameError: Name 'z' is not defined")
  assert fix_python_syntax(def test():
      x = 5
      y = 3
      z)==def test():
      x = 5
      y = 3
      z
  assert fix_python_syntax([])==''
  assert fix_python_syntax('')==''
output: def fix_python_syntax(code_snippet):
      if not code_snippet:
          return ''
      try:
          compile(code_snippet, '<string>', 'exec')
          return code_snippet
      except SyntaxError as e:
          lines = code_snippet.split('\n')
          if e.lineno and e.offset:
              line_index = e.lineno - 1
              error_line = lines[line_index]
              if e.msg == "invalid syntax":
                  if error_line.strip().endswith(':'):
                      lines[line_index] = error_line.rstrip(':')
                  elif error_line.strip().endswith(','):
                      lines[line_index] = error_line.rstrip(',')
              elif e.msg == "expected ':'":
                  if not error_line.strip().endswith(':'):
                      lines[line_index] = error_line + ':'
              code_snippet = '\n'.join(lines)
              try:
                  compile(code_snippet, '<string>', 'exec')
                  return code_snippet
              except SyntaxError:
                  pass
          return code_snippet