old_contents: from expressions import core
  
  
  class System(core.BaseType):
      """The most generic type."""
      def __setitem__(self, key, value):
          return self._array.__setitem__(key, value)
  
      def __repr__(self):
          return 'System(%s)' % repr(self._array)
  
  
  def solve(system):
      variable = system._generator.gi_code.co_varnames[1:][0]
      expression = system._expression.replace("==","-(") + ")"
      c = eval(expression, {variable: 1j})
      return {variable: -c.real/c.imag}
new_contents: from expressions import core
  
  
  def solve_single_equality(equality, variable):
      expression = equality.replace("==","-(") + ")"
      c = eval(expression, {variable: 1j})
      return {variable: -c.real/c.imag}
  
  
  def solve(system):
      variable = system._generator.gi_code.co_varnames[1:][0]
      return solve_single_equality(system._expression, variable)
  
  
  def extract_coefficients(system):
      print(system._expression)
      # equalities = system._expression.split('|')
      # equality 
  
subject: remove the System class and refactor the solve function0