code: def peep_install(argv):
      
      output = []
      out = output.append
      reqs = []
      try:
          req_paths = list(requirement_args(argv, want_paths=True))
          if not req_paths:
              out("You have to specify one or more requirements files with the -r option, because\n"
                  "otherwise there's nowhere for peep to look up the hashes.\n")
              return COMMAND_LINE_ERROR
  
          # We're a "peep install" command, and we have some requirement paths.
          reqs = list(chain.from_iterable(
              downloaded_reqs_from_path(path, argv)
              for path in req_paths))
          buckets = bucket(reqs, lambda r: r.__class__)
  
          # Skip a line after pip's "Cleaning up..." so the important stuff
          # stands out:
          if any(buckets[b] for b in ERROR_CLASSES):
              out('\n')
  
          printers = (lambda r: out(r.head()),
                      lambda r: out(r.error() + '\n'),
                      lambda r: out(r.foot()))
          for c in ERROR_CLASSES:
              first_every_last(buckets[c], *printers)
  
          if any(buckets[b] for b in ERROR_CLASSES):
              out('-------------------------------\n'
                  'Not proceeding to installation.\n')
              return SOMETHING_WENT_WRONG
          else:
              for req in buckets[InstallableReq]:
                  req.install()
  
              first_every_last(buckets[SatisfiedReq], *printers)
  
          return ITS_FINE_ITS_FINE
      except (UnsupportedRequirementError, InstallationError, DownloadError) as exc:
          out(str(exc))
          return SOMETHING_WENT_WRONG
      finally:
          for req in reqs:
              req.dispose()
          print(''.join(output))
docs: Perform the ``peep install`` subcommand, returning a shell status code
      or raising a PipException.
  
      :arg argv: The commandline args, starting after the subcommand