#
  # NOTE: This procedure attempts to extract the lookup code from the raw
  #       HTTP response data.  The data argument is the raw HTTP response
  #       data.  An empty string is returned if no lookup code is available.
  #
  # <internal>
  proc getResponseCodeFromRawData { data } {
    if {![stringIsList $data] || [llength $data] < 1} then {
      return ""
    }

    return [lindex $data 0]
  }

  #
  # NOTE: This procedure attempts to extract the lookup result from the raw
  #       HTTP response data.  The data argument is the raw HTTP response
  #       data.  An empty string is returned if no lookup result is available.
  #
  # <internal>
  proc getResponseResultFromData { data } {
    if {![stringIsList $data] || [llength $data] < 2} then {
      return ""
    }

    return [lindex $data 1]
  }

  #
  # NOTE: This procedure returns non-zero if the specified lookup response
  #       code indicates success.  The code argument is the extracted HTTP
  #       lookup response code.
  #
  # <internal>
  proc isResponseCodeOk { code } {
    #
    # NOTE: The code must be the literal string "OK" for the package lookup
    #       request to be considered successful.
    #
    return [expr {$code eq "OK"}]
  }


    #
    set data [getLookupData $apiKeys $package $version]

    #
    # NOTE: Attempt to grab the lookup code from the non-anonymous
    #       response data.
    #
    set code [getResponseCodeFromRawData $data]

    #
    # NOTE: If necessary, fallback with to an anonymous request.
    #
    if {![isResponseCodeOk $code]} then {
      #
      # NOTE: Issue the anonymous lookup request to the remote
      #       package repository.
      #
      set data [getLookupData [list] $package $version]

      #
      # NOTE: Attempt to grab the lookup code from the anonymous
      #       response data.
      #
      set code [getResponseCodeFromRawData $data]
    }

    #
    # NOTE: Attempt to grab the lookup data from the response data.
    #       Upon failure, this should contain the error message.
    #
    set result [getResponseResultFromData $data]

    #
    # NOTE: Did the lookup operation fail?
    #
    if {![isResponseCodeOk $code]} then {
      #
      # NOTE: Is there an error message?
      #
      if {[string length $result] > 0} then {
        #
        # NOTE: Yes.  Use the returned error message verbatim.
        #