def parse_acl(xml)
      grants = {}
      rexml_document(xml).elements.each("AccessControlPolicy/AccessControlList/Grant") do |grant|
        grants.merge!(extract_grantee(grant))
      end
      grants
    end
def parse_acl(xml)
      grants = {}
      rexml_document(xml).elements.each("AccessControlPolicy/AccessControlList/Grant") do |grant|
        grants.merge!(extract_grantee(grant))
      end
      grants
    end
Parse acl response and return hash with grantee and their permissions