[Python] Petalinux installer reports "Python version is less than 2.7.3" despite having Python...

I'm trying to install Petalinux on Ubuntu 20.04 and encountering a strange error during installation.

Even though I have Python 2.7.18 correctly installed and accessible via the python command, the installer reports the following:

j@j-com:~/다운로드$ python --version
Python 2.7.18

@j-com:~/다운로드$ ./petalinux-v2017.4-final-installer.run /opt/pkg/petalinux

INFO: Checking installer checksum...
INFO: Extracting PetaLinux installer...

LICENSE AGREEMENTS

PetaLinux SDK contains software from a number of sources. Please review
the following licenses and indicate your acceptance of each to continue.

You do not have to accept the licenses, however if you do not then you may
not use PetaLinux SDK.

Use PgUp/PgDn to navigate the license viewer, and press 'q' to close

Press Enter to display the license agreements
Do you accept Xilinx End User License Agreement? [y/N] >
Do you accept Xilinx End User License Agreement? [y/N] > y
Do you accept Webtalk Terms and Conditions? [y/N] > y
Do you accept Third Party End User License Agreement? [y/N] > y
INFO: Checking installation environment requirements...
INFO: Checking free disk space
INFO: Checking installed tools
dpkg-query: 패키지 'python'는 설치되지 않았으며 정보가 없습니다
Use dpkg --info (= dpkg-deb --info) to examine archive files.
environment: 줄 315: ( 10#34+ > 10#24: 문법 오류: 피연산자 필요함 (오류 토큰은 "> 10#24" 임)
environment: 줄 319: ( 10#34+ < 10#24: 문법 오류: 피연산자 필요함 (오류 토큰은 "< 10#24" 임)
ERROR: You have tools don't meet the version requrements:

-Detected python version is less than the expected 2.7.3

INFO: Checking installed development libraries
Please install them with your operating system package manager, and try again
WARNING: Please install required packages.

Please refer to the PetaLinux Tools Installation Guide.

Check the troubleshooting guide at the end of that manual, and if you are
unable to resolve the issue please contact customer support with file:
/home/j/다운로드/petalinux_installation_log

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