@timesheet_lines=[
    #<XeroRuby::PayrollAu::TimesheetLine:0x00007fa052d99258 
        @earnings_rate_id="4c099b8b-8fe3-436d-973e-0e17c01146a0", 
        @number_of_units=[0.0, 0.0, 0.0, 0.0, 4.0, 0.0, 0.0], 
        @updated_date_utc=Wed, 28 Jun 2023 05:28:34 +0000>
   ]

def _to_hash(value, downcase: false)
  if value.is_a?(Array)
    value.map do |v|
      v.to_hash(downcase: downcase) # <- the problematic part, because it doesn't check if the value responds to to_hash
    end
  elsif value.is_a?(Hash)
    {}.tap do |hash|
      value.map { |k, v| hash[k] = _to_hash(v, downcase: downcase) }
    end
  elsif value.respond_to? :to_hash
    value.to_hash(downcase: downcase)
  else
    value
  end
end