old_contents: import hashlib
  
  import groestlcoin_hash
  
  from pycoin.encoding.hexbytes import bytes_as_revhex
  
  
  def sha256(data):
      return bytes_as_revhex(hashlib.sha256(data).digest())
  
  
  def groestlHash(data):
      """Groestl-512 compound hash."""
      return bytes_as_revhex(groestlcoin_hash.getHash(data, len(data)))
  
new_contents: import hashlib
  
  from pycoin.encoding.hexbytes import bytes_as_revhex
  
  
  def sha256(data):
      return bytes_as_revhex(hashlib.sha256(data).digest())
  
  
  def groestlHash(data):
      """Groestl-512 compound hash."""
      try:
          import groestlcoin_hash
      except ImportError:
          t = 'Groestlcoin requires the groestlcoin_hash package ("pip install groestlcoin_hash").'
          print(t)
          raise ImportError(t)
  
      return bytes_as_revhex(groestlcoin_hash.getHash(data, len(data)))
  
subject: Raise ImportError when GRS is used without dependency