<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def copy_current_file_offset():
 """Get the file-offset mapped to the current address."""

    start, end = sark.get_selection()

    try:
        file_offset = sark.core.get_fileregion_offset(start)
        clipboard.copy("0x{:08X}".format(file_offset))

    except sark.exceptions.NoFileOffset:
        message("The current address cannot be mapped to a valid offset of the input file.")