code: def require(*args, **kwargs):
      '''
      Install a set of packages using pip
      
      This is designed to be an interface for IPython notebooks that
      replicates the requirements.txt pip format. This lets notebooks
      specify which versions of packages they need inside the notebook
      itself.
  
      This function is the general-purpose interface that lets
      the caller specify any version string for any package.
  
      '''
      # If called with no arguments, returns requirements list
      if not args and not kwargs:
          return freeze()
  
      # Construct array of requirements
      requirements = list(args)
      extra = ['{}{}'.format(kw, kwargs[kw]) for kw in kwargs]
      requirements.extend(extra)
      args = ['install', '-q']
      args.extend(requirements)
      pip.main(argsf require(*args, **kwargs):
      '''
      Install a set of packages using pip
      
      This is designed to be an interface for IPython notebooks that
      replicates the requirements.txt pip format. This lets notebooks
      specify which versions of packages they need inside the notebook
      itself.
  
      This function is the general-purpose interface that lets
      the caller specify any version string for any package.
  
      '''
      # If called with no arguments, returns requirements list
      if not args and not kwargs:
          return freeze()
  
      # Construct array of requirements
      requirements = list(args)
      extra = ['{}{}'.format(kw, kwargs[kw]) for kw in kwargs]
      requirements.extend(extra)
      args = ['install', '-q']
      args.extend(requirements)
      pip.main(args)
docs: Install a set of packages using pip
      
      This is designed to be an interface for IPython notebooks that
      replicates the requirements.txt pip format. This lets notebooks
      specify which versions of packages they need inside the notebook
      itself.
  
      This function is the general-purpose interface that lets
      the caller specify any version string for any package.