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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 _isFileAccessible(filepath):
 """Returns True if the specified filepath is writable."""

    directory = os.path.dirname(filepath)
    if not os.access(directory, os.W_OK):
        #Return False if directory does not exist or is not writable
        return False
    if os.path.exists(filepath):
        if not os.access(filepath, os.W_OK):
            #Return False if file is not writable
            return False
        try:
            openfile = os.open(filepath, os.O_WRONLY)
            os.close(openfile)
        except IOError:
            #Return False if file is locked
            return False
    #Return True if file is writtable
    return True