def inspect
      @terms.map do |var, coeff|
        # Skip if the coefficient is zero or the value is zero
        value = var.value
        next if coeff == 0 || value == 0 || value == false

        coeff == 1 ? var.name : "#{var.name} * #{coeff}"
      end.compact.join(' + ')
    end
def inspect
      @terms.map do |var, coeff|
        # Skip if the coefficient is zero or the value is zero
        value = var.value
        next if coeff == 0 || value == 0 || value == false

        coeff == 1 ? var.name : "#{var.name} * #{coeff}"
      end.compact.join(' + ')
    end
Produce a string representing the expression