@classmethod
def from_redshift(cls, sql, username=None, password=None, host=None, db=
    None, port=None):
    """
        Create a ``parsons table`` from a Redshift query.

        To pull an entire Redshift table, use a query like ``SELECT * FROM tablename``.

        `Args:`
            sql: str
                A valid SQL statement
            username: str
                Required if env variable ``REDSHIFT_USERNAME`` not populated
            password: str
                Required if env variable ``REDSHIFT_PASSWORD`` not populated
            host: str
                Required if env variable ``REDSHIFT_HOST`` not populated
            db: str
                Required if env variable ``REDSHIFT_DB`` not populated
            port: int
                Required if env variable ``REDSHIFT_PORT`` not populated. Port 5439 is typical.

        `Returns:`
            Parsons Table
                See :ref:`parsons-table` for output options.
        """
    from parsons.databases.redshift import Redshift
    rs = Redshift(username=username, password=password, host=host, db=db,
        port=port)
    return rs.query(sql)
