class_docstr: FileInput([files[, inplace[, backup]]], *, mode=None, openhook=None)
  
  Class FileInput is the implementation of the module; its methods
  filename(), lineno(), fileline(), isfirstline(), isstdin(), fileno(),
  nextfile() and close() correspond to the functions of the same name
  in the module.
  In addition it has a readline() method which returns the next
  input line, and a __getitem__() method which implements the
  sequence behavior. The sequence must be accessed in strictly
  sequential order; random access and readline() cannot be mixed.
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code: def fileno(self):
      if self._file:
          try:
              return self._file.fileno()
          except ValueError:
              return -1
      else:
          return -1
  
imports: import io
  import sys, os
  from types import GenericAlias
label_desc: Use image node_id 14 for calling the FileInput obj's underlying member method code with example usage: obj.fileno() and returns: unknown, self, unknown