code: def p_width(self, p):
          'width : LBRACKET expression COLON expression RBRACKET'
          p[0] = Width(p[2], p[4], lineno=p.lineno(1))
          p.set_lineno(0, p.lineno(1)f p_width(self, p):
          'width : LBRACKET expression COLON expression RBRACKET'
          p[0] = Width(p[2], p[4], lineno=p.lineno(1))
          p.set_lineno(0, p.lineno(1))
docs: width : LBRACKET expression COLON expression RBRACKET