changing default x range in histogram matplotlib

the following code is for making the same y axis limit on two subplots

f ,ax = plt.subplots(1,2,figsize = (30, 13),gridspec_kw={'width_ratios': [5, 1]})
df.plot(ax = ax[0], linewidth = 2.5)
ylim = [lower_limit,upper_limit]
ax[0].set_ylim(ylim)
ax[1].hist(data,normed =1, bins = num_bin, color = 'yellow' ,alpha = 1) 
ax[1].set_ylim(ylim)

just a reminder, plt.hist(range=[low, high]) the histogram auto crops the range if the specified range is larger than the max&min of the data points. So if you want to specify the y-axis range number, i prefer to use set_ylim

plt.hist(hmag, 30, range=[6.5, 12.5], facecolor='gray', align='mid')

import matplotlib.pyplot as plt


...


plt.xlim(xmin=6.5, xmax = 12.5)