```ruby
require_dependency 'extract_emails'

class Project

  # array of user IDs
  attr_accessor :invite_users
  # string with email addresses
  attr_accessor :invite_emails
  attr_accessor :invite_role
  attr_accessor :invitations_locale

  # if any of the invitation parameters are defined, send invitations
  def invite_people?
    invite_users.present? or invite_emails.present?
  end
  
  def invite_role
    @invite_role || Person::ROLES[:admin]
  end

  after_create :send_invitations!, :if => :invite_people?

  def send_invitations!
    return unless invite_people?
    users_to_invite = User.find(Array.wrap invite_users)
    emails_to_invite = invite_emails.to_s.extract_emails - users_to_invite.map(&:email)
    the_role = invite_role
    
    for user in users_to_invite
      create_invitation(self.user, :invited_user => user, :role => the_role)
    end

    for email in emails_to_invite
      create_invitation(self.user, :user_or_email => email, :locale => invitations_locale, :role => the_role)
    end
  end

end
```

Use 'require', not 'require_dependency' in extract_emails
user
```ruby
require 'extract_emails'

class Project

  # array of user IDs
  attr_accessor :invite_users
  # string with email addresses
  attr_accessor :invite_emails
  attr_accessor :invite_role
  attr_accessor :invitations_locale

  # if any of the invitation parameters are defined, send invitations
  def invite_people?
    invite_users.present? or invite_emails.present?
  end
  
  def invite_role
    @invite_role || Person::ROLES[:admin]
  end

  after_create :send_invitations!, :if => :invite_people?

  def send_invitations!
    return unless invite_people?
    users_to_invite = User.find(Array.wrap invite_users)
    emails_to_invite = invite_emails.to_s.extract_emails - users_to_invite.map(&:email)
    the_role = invite_role
    
    for user in users_to_invite
      create_invitation(self.user, :invited_user => user, :role => the_role)
    end

    for email in emails_to_invite
      create_invitation(self.user, :user_or_email => email, :locale => invitations_locale, :role => the_role)
    end
  end

end
```
assistant