code: def get_sqlalchemy_url(database=None, host=None, port=None, username=None, password=None, driver='postgres'):
          # type: (Optional[str], Optional[str], Union[int, str, None], Optional[str], Optional[str], str) -> str
          
          strings = ['%s://' % driver]
          if username:
              strings.append(username)
              if password:
                  strings.append(':%s@' % password)
              else:
                  strings.append('@')
          if host:
              strings.append(host)
          if port is not None:
              strings.append(':%d' % int(port))
          if database:
              strings.append('/%s' % database)
          return ''.join(strings)
docs: Gets SQLAlchemy url from database connection parameters
  
          Args:
              database (Optional[str]): Database name
              host (Optional[str]): Host where database is located
              port (Union[int, str, None]): Database port
              username (Optional[str]): Username to log into database
              password (Optional[str]): Password to log into database
              driver (str): Database driver. Defaults to 'postgres'.
  
          Returns:
              db_url (str): SQLAlchemy url