def robotsrulesetOfDomain(self, domain):
		'''检查domain是否在数据库中,
			否 --> (False, None)
			是 --> (True, 数据库中存储的robots.txt内容)
		'''
		exist = False
		cur = self.conn.cursor()
		# 是否存在
		cur.execute("SELECT 1 FROM Domains WHERE domain=?", (domain,))
		if cur.fetchone() :
			exist = True
		# 存在的话,结果是什么
		cur.execute("SELECT rules FROM Domains,Rulesets "
			"WHERE domain=? AND Domains.did=Rulesets.did"
			,(domain,) )
		ruleset = cur.fetchone()
		return (exist, ruleset)
def felosses(losses, coeffs, title='', log=True, ax=0):
    """plot iron losses with steinmetz or jordan approximation
    Args:
      losses: dict with f, B, pfe values
      coeffs: list with steinmetz (cw, alpha, beta) or
              jordan (cw, alpha, ch, beta, gamma) coeffs
      title: title string
      log: log scale for x and y axes if True

    """
    import femagtools.losscoeffs as lc
    if ax == 0:
        ax = plt.gca()

    fo = losses['fo']
    Bo = losses['Bo']
    B = plt.np.linspace(0.9*np.min(losses['B']),
                        1.1*0.9*np.max(losses['B']))

    for i, f in enumerate(losses['f']):
        pfe = [p for p in np.array(losses['pfe'])[i] if p]
        if f > 0:
            if len(coeffs) == 5:
                ax.plot(B, lc.pfe_jordan(f, B, *coeffs, fo=fo, Bo=Bo))
            elif len(coeffs) == 3:
                ax.plot(B, lc.pfe_steinmetz(f, B, *coeffs, fo=fo, Bo=Bo))
        plt.plot(losses['B'][:len(pfe)], pfe,
                 marker='o', label="{} Hz".format(f))

    ax.set_title("Fe Losses/(W/kg) " + title)
    if log:
        ax.set_yscale('log')
        ax.set_xscale('log')
    ax.set_xlabel("Flux Density [T]")
    # plt.ylabel("Pfe [W/kg]")
    ax.legend()
    ax.grid(True)