code: def convert_requirement(req):
      
      pkg_name = convert_name(req.project_name)
      if not req.specs:
          return [pkg_name]
  
      req_strs = []
      for spec in req.specs:
          op, ver = spec
          ver = convert_version(ver)
          if op == "<":
              r = "%s-0+<%s" % (pkg_name, ver)
              req_strs.append(r)
          elif op == "<=":
              r = "%s-0+<%s|%s" % (pkg_name, ver, ver)
              req_strs.append(r)
          elif op == "==":
              r = "%s-%s" % (pkg_name, ver)
              req_strs.append(r)
          elif op == ">=":
              r = "%s-%s+" % (pkg_name, ver)
              req_strs.append(r)
          elif op == ">":
              r1 = "%s-%s+" % (pkg_name, ver)
              r2 = "!%s-%s" % (pkg_name, ver)
              req_strs.append(r1)
              req_strs.append(r2)
          elif op == "!=":
              r = "!%s-%s" % (pkg_name, ver)
              req_strs.append(r)
          else:
              print >> sys.stderr, \
                  "Warning: Can't understand op '%s', just depending on unversioned package..." % op
              req_strs.append(pkg_name)
  
      return req_strs
docs: Converts a pkg_resources.Requirement object into a list of Rez package
      request strings.