code: def SignedVarintEncode(value):
    
    result = b""
    if value < 0:
      value += (1 << 64)
  
    bits = value & 0x7f
    value >>= 7
    while value:
      result += HIGH_CHR_MAP[bits]
      bits = value & 0x7f
      value >>= 7
    result += CHR_MAP[bits]
  
    return result
docs: Encode a signed integer as a zigzag encoded signed integer.