class Net::IMAP::StringPrep::StringPrepError

profile.
ArgumentError raised when string is invalid for the stringprep

def initialize(*args, string: nil, profile: nil) 

def initialize(*args, string: nil, profile: nil)
  @string  = -string.to_str  unless string.nil?
  @profile = -profile.to_str unless profile.nil?
  super(*args)
end