rubytest

gistfile1.txt

require "peddler"
client = MWS::Reports::Client.new(
  primary_marketplace_id: "X",
  merchant_id: "X",
  aws_access_key_id: "X",
  aws_secret_access_key: "X"
)
reports = client.get_report_request_list()
parser = client.get_report_request_list
parser.parse

line 8/9 should be
reports = parser = client.get_report_request_list

#get_report_request_list isn't a pure function, so if you call it twice to define two vars, they might not end up the same
Also, you don't need () at the end of a function to call it.

Although, as I've just discovered in pry, this makes reports and parsers point to the same object rather than 2 identical ones. so if you modify parser, reports would also change