code: def from_epsg(self, epsg_code):
          
          self.epsg_code = epsg_code
          assert isinstance(self.epsg_code, int)
          cur = self.conn.cursor()
          cur.execute("SELECT prjtext FROM prj_epsg WHERE epsg_code = ?", (self.epsg_code,))
          result = cur.fetchone()
          if result is not None:
              self.prj = result[0]
              return True
  
          return False
docs: Loads self.prj by epsg_code.
          If prjtext not found returns False.