关于python字典的问题 这段代码因该怎么解决这个问题啊

KeyError                                  Traceback (most recent call last)
<ipython-input-32-440e5b999955> in <module>
      8 print(fname)
      9 print(mname)
---> 10 f_subjXtc,f_mtx_r=tc2fc_r(fname,167,121,root,'fullR')
     11 m_subjXtc,m_mtx_r=tc2fc_r(mname,167,121,root,'fullR')

<ipython-input-31-8dc258cf8552> in tc2fc_r(subjname, nodes_num, tp, root, method)
      5         dataFile=root+subjname.iloc[i]+'.mat'
      6         data=scio.loadmat(dataFile)
----> 7         tc=data[subjname.iloc[i]]
      8         subjXtc[i,:,:]=tc
      9     print(nodes_num,'node tc matrix=',subjXtc.shape)

KeyError: 'sub1'

这个字典没有键sub1