# File lib/simplecov/source_file.rb, line 24
      def initialize(src, line_number, coverage)
        raise ArgumentError, "Only String accepted for source" unless src.kind_of?(String)
        raise ArgumentError, "Only Fixnum accepted for line_number" unless line_number.kind_of?(Fixnum)
        raise ArgumentError, "Only Fixnum and nil accepted for coverage" unless coverage.kind_of?(Fixnum) or coverage.nil?
        @src, @line_number, @coverage = src, line_number, coverage
      end