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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ReadVFS(pathspec, offset, length, progress_callback=None):
 """Read from the VFS and return the contents. Args: pathspec: path to read from offset: number of bytes to skip length: number of bytes to read progress_callback: A callback to indicate that the open call is still working but needs more time. Returns: VFS file contents """

  fd = VFSOpen(pathspec, progress_callback=progress_callback)
  fd.Seek(offset)
  return fd.Read(length)