```ruby
require 'ripper'

##
# Uses the ripper parser to analyze ruby code contained in gems
# and raises warnings if the code has potential issues.

class Gem::Analyzer < Ripper::SexpBuilder

  ##
  # Cache of issues found for the current session.

  attr_reader :warnings

  ##
  # Check the given string of code for potential issues when compiled.
  # Returns the analyzer instance afterwards.

  def check code
    @parser ||= Gem::Analyzer.new(code)
    parser.parse
    parser
  end

  def parse
    @warnings = []
    super
  end

  def on_kw token
    # Related to MacRuby ticket #721
    if token == '__FILE__'
      @warnings << '__FILE__ keyword is used (MacRuby ticket #721)'
    end
  end

end
```

Fix a couple of typos
user
```ruby
require 'ripper'

##
# Uses the ripper parser to analyze ruby code contained in gems
# and raises warnings if the code has potential issues.

class Gem::Analyzer < Ripper::SexpBuilder

  ##
  # Cache of issues found for the current session.

  attr_reader :warnings

  ##
  # Check the given string of code for potential issues when compiled.
  # Returns the analyzer instance afterwards.

  def self.check code
    @parser ||= Gem::Analyzer.new(code)
    @parser.parse
    @parser
  end

  def parse
    @warnings = []
    super
  end

  def on_kw token
    # Related to MacRuby ticket #721
    if token == '__FILE__'
      @warnings << '__FILE__ keyword is used (MacRuby ticket #721)'
    end
  end

end
```
assistant