docs: def filter_by(lookup_dict,
                pillar,
                merge=None,
                default='default',
                base=None):
      '''
      .. versionadded:: 2017.7.0
  
      Look up the given pillar in a given dictionary and return the result
  
      :param lookup_dict: A dictionary, keyed by a pillar, containing a value or
          values relevant to systems matching that pillar. For example, a key
          could be a pillar for a role and the value could the name of a package
          on that particular OS.
  
          The dictionary key can be a globbing pattern. The function will return
          the corresponding ``lookup_dict`` value where the pillar value matches
          the  pattern. For example:
  
          .. code-block:: bash
  
              # this will render 'got some salt' if ``role`` begins with 'salt'
              salt '*' pillar.filter_by '{salt*: got some salt, default: salt is not here}' role
  
      :param pillar: The name of a pillar to match with the system's pillar. For
          example, the value of the "role" pillar could be used to pull values
          from the ``lookup_dict`` dictionary.
  
          The pillar value can be a list. The function will return the
          ``lookup_dict`` value for a first found item in the list matching
          one of the ``lookup_dict`` keys.
  
      :param merge: A dictionary to merge with the results of the pillar
          selection from ``lookup_dict``. This allows another dictionary to
          override the values in the ``lookup_dict``.
  
      :param default: default lookup_dict's key used if the pillar does not exist
          or if the pillar value has no match on lookup_dict.  If unspecified
          the value is "default".
  
      :param base: A lookup_dict key to use for a base dictionary.  The
          pillar-selected ``lookup_dict`` is merged over this and then finally
          the ``merge`` dictionary is merged.  This allows common values for
          each case to be collected in the base and overridden by the pillar
          selection dictionary and the merge dictionary.  Default is unset.
  
      CLI Example:
  
      .. code-block:: bash
  
          salt '*' pillar.filter_by '{web: Serve it up, db: I query, default: x_x}' role
      '''
      return salt.utils.data.filter_by(lookup_dict=lookup_dict,
                                       lookup=pillar,
                                       traverse=__pillar__,
                                       merge=merge,
                                       default=default,
                                       base=base)