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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 com_google_fonts_check_linegaps(ttFont):
 """Checking Vertical Metric Linegaps."""

  if ttFont["hhea"].lineGap != 0:
    yield WARN, Message("hhea", "hhea lineGap is not equal to 0.")
  elif ttFont["OS/2"].sTypoLineGap != 0:
    yield WARN, Message("OS/2", "OS/2 sTypoLineGap is not equal to 0.")
  else:
    yield PASS, "OS/2 sTypoLineGap and hhea lineGap are both 0."