def decipher_atom_key(atom_key, forcefield):
load_funcs = {<EOL>'<STR_LIT>': dlf_notation,<EOL>'<STR_LIT>': dlf_notation,<EOL>'<STR_LIT>': opls_notation,<EOL>'<STR_LIT>': opls_notation,<EOL>'<STR_LIT>': opls_notation,<EOL>'<STR_LIT>': opls_notation,<EOL>}<EOL>if forcefield.upper() in load_funcs.keys():<EOL><INDENT>return load_funcs[forcefield.upper()](atom_key)<EOL><DEDENT>else:<EOL><INDENT>raise _ForceFieldError(<EOL>("<STR_LIT>"<EOL>"<STR_LIT>"<EOL>"<STR_LIT>"<EOL>).format(forcefield))<EOL><DEDENT>
Return element for deciphered atom key.

This functions checks if the forcfield specified by user is supported
and passes the atom key to the appropriate function for deciphering.

Parameters
----------
atom_key : str
    The atom key which is to be deciphered.

forcefield : str
    The forcefield to which the atom key belongs to.

Returns
-------
str
    A string that is the periodic table element equvalent of forcefield
    atom key.