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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 get_command(self, command):
 		"""Helper function for osx - return gnu utils rather than default for 		 eg head and md5sum where possible and needed. 		"""

		shutit_global.shutit_global_object.yield_to_draw()
		if command in ('md5sum','sed','head'):
			if self.get_current_shutit_pexpect_session_environment().distro == 'osx':
				return 'g' + command
		return command