docs: def execute_sql(self, query):
          """
          Executes a given query string on an open postgres database.
  
          """
          c = self.con.cursor()
          c.execute(query)
          result = []
          if c.rowcount > 0:
              try:
                  result = c.fetchall()
              except psycopg2.ProgrammingError:
                  pass
          return result