module HTTParty::ClassMethods

def pem(pem_contents, password = nil)

end
pem File.read('/home/user/my.pem'), "optional password"
include HTTParty
class Foo

Allows setting a PEM file to be used
def pem(pem_contents, password = nil)
  default_options[:pem] = pem_contents
  default_options[:pem_password] = password
end