input: Write a function to convert a given Python program to a C# program. The function should take in a string representation of a Python function and return a string representation of the equivalent C# function.
  
  public string ConvertPythonToCSharp(string pythonCode)
  
  assert ConvertPythonToCSharp("def power(x, y):\n    if y == 0:\n        return 1\n    else:\n        return x * power(x, y - 1)") == "public int Power(int x, int y)\n{\n    if (y == 0)\n    {\n        return 1;\n    }\n    else\n    {\n        return x * Power(x, y - 1);\n    }\n}"
output: 
  def ConvertPythonToCSharp(pythonCode):
      lines = pythonCode.split('\n')
      csharpCode = []
      for line in lines:
          if line.startswith('def '):
              line = line.replace('def ', 'public ').replace(':', '')
              line = line.replace('int ', 'int ').replace('float ', 'float ').replace('str ', 'string ')
              line = line.replace('(', '(').replace(')', ')')
              line = line + '\n{'
          else:
              line = line.replace('    ', '    ')
              line = line.replace('return ', 'return ').replace('return 1', 'return 1;').replace('return x * power(x, y - 1)', 'return x * Power(x, y - 1);')
              line = line.replace('if ', 'if (').replace(':', ')')
              line = line.replace('else:', 'else')
          csharpCode.append(line)
      csharpCode.append('}')
      return '\n'.join(csharpCode)
  