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Interpreter Information Functions

Documentation for copyright, credits, and license - Python interpreter information objects.

These three names are not functions and not strings. They are instances of _sitebuiltins._Printer, installed into builtins by the site module during interpreter startup. Displaying one calls its __repr__, which is why typing the bare name in the REPL prints text.

Complexity Reference

Operation	Time	Space	Notes
copyright (display)	O(n)	O(n)	11 lines, under the limit, so the text is returned
credits (display)	O(n)	O(n)	2 lines, under the limit
license (first display)	O(n)	O(n)	Reads and caches the LICENSE file; n = file size
license (later displays)	O(1)	O(1)	Cached, and the result is a fixed one-line hint
str(obj) / repr(obj)	O(n)	O(n)	n = text length, but see the line limit below
obj() (call)	O(n)	O(1)	Pages through the text, 23 lines at a time

Two things drive the cost, and neither is obvious from the names.

The text is loaded lazily. copyright and credits carry their text inline (307 and 158 characters). license carries filenames instead and reads one the first time it is displayed, so only its first use is O(n) in the file.

Display is capped at MAXLINES (23). __repr__ returns the joined text only when the content fits in that many lines. Above it, you get a fixed one-line hint instead. copyright is 11 lines and prints in full; license is around 280 lines and does not.

What These Objects Are

# O(1) - attribute and type lookups
print(type(copyright))             # O(1) - <class '_sitebuiltins._Printer'>
print(isinstance(copyright, str))  # O(1) - False

# The text comes from __repr__, not from the object being a string
text = repr(copyright)             # O(n) - n = length of the text
print(len(text))                   # O(1) - 307

All three share the same type; they differ only in the text they carry and where it comes from.

Copyright Information

copyright - Python Copyright

Eleven lines of text, held inline, so it prints in full.

# O(n) - n = length of the embedded text
print(copyright)

# Output:
# Copyright (c) 2001-2024 Python Software Foundation.
# All Rights Reserved.
#
# Copyright (c) 2000 BeOpen.com
# All Rights Reserved.
#
# ...

The same text is available as the plain string sys.copyright, which exists even when site is disabled - see sys Module.

import sys

# O(n) - str() invokes __repr__ and produces the same characters
print(str(copyright) == sys.copyright)   # True

Credits Information

credits - Python Credits

Two lines of text, held inline.

# O(n) - n = length of the embedded text
print(credits)

# Output:
#     Thanks to CWI, CNRI, BeOpen.com, Zope Corporation and a cast of thousands
#     for supporting Python development.  See www.python.org for more information.

There is no sys.credits. To get the text in code, convert the object.

# O(n) - formatting invokes __repr__, n = length of the text
message = f"Credits: {credits}"

# O(n) - equivalent, and clearer about what is happening
message = "Credits: " + str(credits)

License Information

license - Python License

Unlike the other two, printing it does not show the license: at around 280 lines it exceeds the 23-line display limit, so you get a hint instead.

# O(n) on first use - reads and caches the LICENSE file, then returns a hint
print(license)
# Type license() to see the full license text

# O(n) - calling it pages through the real text, 23 lines at a time
# license()   # interactive: prompts "Hit Return for more, or q ... to quit"

The Lazy Read

license is the one object here with a cost worth knowing about. It stores filenames rather than text and reads the file on first display - even though the value it returns is the short hint.

import time

# O(n) - first access reads roughly 280 lines from disk
start = time.perf_counter()
first = str(license)
first_us = (time.perf_counter() - start) * 1e6

# O(1) - the lines are now cached on the object
start = time.perf_counter()
second = str(license)
second_us = (time.perf_counter() - start) * 1e6

print(first == second)                             # True - both are the hint
print(f"{first_us:.0f}us then {second_us:.0f}us")  # ~1000us then ~2us

There is no public accessor for the cached lines, so reading the license text in code means reading the file yourself rather than going through this object.

Availability

All three are installed by the site module. Running with -S skips it, and they disappear.

# O(1) - membership test against the builtins namespace
import builtins

print(hasattr(builtins, "copyright"))   # O(1) - False under python -S

$ python -c "print(copyright)"      # works
$ python -S -c "print(copyright)"   # NameError: name 'copyright' is not defined

Best Practices

✅ Do:

• Treat all three as REPL conveniences
• Use str() when you need the text of copyright or credits
• Call license() rather than printing it, if you want the actual license

❌ Avoid:

• Assuming these are strings - isinstance(copyright, str) is False
• Assuming they exist - they are absent under python -S
• Expecting print(license) to show the license - it prints a hint
• Importing _Printer - it lives in _sitebuiltins, is private, and you do not need it

Related Functions

• help() Function - Interactive help, another introspection builtin
• Exit/Quit - The other REPL-only builtins installed by site
• sys Module - sys.copyright, the plain-string equivalent