during install popfile will show error message like following message.

Generating Pods project
[!] An error occurred while processing the post-install hook of the Podfile.

undefined local variable or method `installer' for #<Pod::Podfile:0x00007fee7794a0f8>
Did you mean?  install!

/Users/peggytsai/Documents/wavegis/Water_ios 下午4.12.08/Podfile:45:in `block (3 levels) in from_ruby'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-core-1.5.3/lib/cocoapods-core/podfile.rb:179:in `post_install!'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:647:in `run_podfile_post_install_hook'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:635:in `block in run_podfile_post_install_hooks'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/user_interface.rb:142:in `message'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:634:in `run_podfile_post_install_hooks'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:186:in `block in generate_pods_project'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/user_interface.rb:64:in `section'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:183:in `generate_pods_project'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/installer.rb:119:in `install!'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/command/install.rb:41:in `run'
/usr/local/lib/ruby/gems/2.5.0/gems/claide-1.0.2/lib/claide/command.rb:334:in `run'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/lib/cocoapods/command.rb:52:in `run'
/usr/local/lib/ruby/gems/2.5.0/gems/cocoapods-1.5.3/bin/pod:55:in `<top (required)>'
/usr/local/bin/pod:23:in `load'
/usr/local/bin/pod:23:in `<main>'

how do i install cocoapods popfile?

[Update] cocoapods version is 1.5.3

[Update] cocoapods