pod install error>>> Unable to determine the platform for the `SocketSwift` target

I downloaded github Socket.swift, created Podfile per installation instruction,
but Cocoapods "pod install" gets the error.

Podfile is:

[![# Uncomment the next line to define a global platform for your project
# platform :ios, '9.0'

source 'https://github.com/CocoaPods/Specs.git'
target 'SocketSwift' do

  # Pods for SocketSwift
  pod 'Socket.swift', '~> 2.4.0'
end][1]][1]

Code is unmodified Socket.swift