code: def get_connection_str(db='gravityspy',
                         host='gravityspy.ciera.northwestern.edu',
                         user=None,
                         passwd=None):
      
      if (not user) or (not passwd):
          user = os.getenv('GRAVITYSPY_DATABASE_USER', None)
          passwd = os.getenv('GRAVITYSPY_DATABASE_PASSWD', None)
  
      if (not user) or (not passwd):
          raise ValueError('Remember to either pass '
                           'or export GRAVITYSPY_DATABASE_USER '
                           'and export GRAVITYSPY_DATABASE_PASSWD in order '
                           'to access the Gravity Spy Data: '
                           'https://secrets.ligo.org/secrets/144/'
                           ' description is username and secret is password.')
  
      return 'postgresql://{0}:{1}@{2}:5432/{3}'.format(user, passwd, host, db)
docs: Create string to pass to create_engine
  
      Parameters
      ----------
      db : `str`, default: ``gravityspy``
          The name of the SQL database your connecting to.
  
      host : `str`, default: ``gravityspy.ciera.northwestern.edu``
          The name of the server the database you are connecting to
          lives on.
  
      user : `str`, default: `None`
          Your username for authentication to this database.
  
      passwd : `str`, default: `None`
          Your password for authentication to this database.
  
      .. note::
  
         `user` and `passwd` should be given together, otherwise they will be
         ignored and values will be resolved from the
         ``GRAVITYSPY_DATABASE_USER`` and ``GRAVITYSPY_DATABASE_PASSWD``
         environment variables.
  
      Returns
      -------
      conn_string : `str`
          A SQLAlchemy engine compliant connection string