Why do I have a KeyError, and how can I fix this (Python)?

Question

I am trying to extract some data from a .dat file so I can graph it using Python. However, I am experiencing a KeyError. This is the code that I have written.

fig, axs = plt.subplots(1, nno, figsize=(19,12), sharey=True)

for i in np.arange(nno):    
    atoms = ase.io.read(objs[i].scffile(), format='espresso-in') 
    full_attach_charges(atoms, objs[i].path+'/XAS/Zn0.opt.in.out/GS/'+'ACF.dat',displacement=None,  valence=True)
    charges = []
    
    for atom in atoms:
        charges.append((atom.symbol, atom.charge))
        #atom number here starting from 1 (and not pythonic 0)
        axs[i].scatter(atom.index+1, atom.charge, c=colors[atom.symbol],edgecolors='black')
    markers = [plt.Line2D([0,0],[0,0],color=color, marker='o', linestyle='') for color in colors.values()]
    axs[i].legend(markers, colors.keys(), numpoints=1)
    axs[i].set_xlabel('Atom number')
    axs[i].set_title(letters[i] + ' ' + names[i]+ ': '+ names[i], loc='left')
    
axs[0].set_ylabel('Bader charge')
print(atoms.info[atom.symbol]['valence'])
#Save plot
plt.savefig('bader.pdf')

This is the error I am getting.

 ---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-23-7ac23d8418f1> in <module>
      6 for i in np.arange(nno):
      7     atoms = ase.io.read(objs[i].scffile(), format='espresso-in')
----> 8     full_attach_charges(atoms, objs[i].path+'/XAS/Zn0.opt.in.out/GS/'+'ACF.dat',displacement=None,  valence=True)
      9     charges = []
     10 

<ipython-input-4-574dffc1a6e5> in full_attach_charges(atoms, fileobj, displacement, valence)
     62             atom = atoms[int(words[0]) - 1]
     63             if valence is True:
---> 64                 atom.charge = atoms.info[atom.symbol]['valence'] - float(words[j])
     65             else:
     66                 atom.charge = atomic_numbers[atom.symbol] - float(words[j])

KeyError: 'H'