code: def checkBim(fileName, minNumber, chromosome):
      
      nbMarkers = 0
      with open(fileName, 'r') as inputFile:
          for line in inputFile:
              row = line.rstrip("\r\n").split("\t")
              if row[0] == chromosome:
                  nbMarkers += 1
      if nbMarkers < minNumber:
          return False
      return True
docs: Checks the BIM file for chrN markers.
  
      :param fileName:
      :param minNumber:
      :param chromosome:
  
      :type fileName: str
      :type minNumber: int
      :type chromosome: str
  
      :returns: ``True`` if there are at least ``minNumber`` markers on
                chromosome ``chromosome``, ``False`` otherwise.