def get_element_mass_dictionary(self):
element_symbols = self.material.elements<EOL>element_masses = self.get_element_masses()<EOL>result = {}<EOL>for s, m in zip(element_symbols, element_masses):<EOL><INDENT>result[s] = m<EOL><DEDENT>return result<EOL>
Determine the masses of elements in the package and return as a
dictionary.

:returns: [kg] A dictionary of element symbols and masses.